High · CVSS 8.4
In the Linux kernel, the following vulnerability has been resolved:
drm/sysfb: ofdrm: Fix integer overflow in fb_size calculation
The framebuffer size calculation `fb_size = linebytes * height` can
overflow when both values are large (e.g., 46341 * 46341 > INT_MAX).
Since linebytes and height are both int types, the multiplication is
performed as int * int, which results in undefined behavior on overflow.
Use check_mul_overflow() to detect and prevent this overflow, consistent
with the approach used in simpledrm.c and corebootdrm.c.
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
drm/pagemap: Fix folio allocation fallback and use-after-put
drm_pagemap_migrate_populate_ram_pfn() had two issues when populating
RAM PFNs with higher-order folios:
1. The higher-order vma_alloc_folio()/folio_alloc() calls did not pass
__GFP_NOWARN, so a THP allocation failure under memory pressure
would spam the kernel log, and there was no fallback path despite a
TODO comment stating one was needed. Add __GFP_NOWARN to the
higher-order allocation and, on failure, fall back to order-0
allocations for the entire range originally covered by the failed
higher-order allocation, leaving MIGRATE_PFN_COMPOUND unset for
those PFNs.
2. In the free_pages error path, order was computed via
folio_order(page_folio(page)) *after* put_page(page) had already
dropped the reference, resulting in a use-after-free/put when that
was the last reference on the page. Compute order before releasing
the page.
Introducing the fallback in 1. also requires the source page array
handed to ->copy_to_ram() to be built differently. Both callers only
populated the entry at the head of each source folio, relying on the
copy callback to derive the rest of the folio from the order recorded
in the matching drm_pagemap_addr. Once the destination has been demoted
to order-0 folios the drm_pagemap_addr entries are per-page, so a source
page is needed for every one of them; leaving them NULL makes the copy
callback stop after the first page and the remainder of the range is
never copied.
The source folio is only split later, by migrate_vma_pages() /
migrate_device_pages(), so its order cannot be used to detect the
demotion - test the destination for MIGRATE_PFN_COMPOUND instead. Factor
the array population out into drm_pagemap_migrate_populate_src_pages()
and use it from both drm_pagemap_evict_to_ram() and
__drm_pagemap_migrate_to_ram().
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 8.8
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau/dmem: fix mismatched DMA unmap size for large folios
Device-private THP migration maps migration buffers with page_size()
and records that length in dma_info->size. For a compound folio
page_size() is PAGE_SIZE << order, but two teardown sites still pass a
literal PAGE_SIZE to dma_unmap_page():
- nouveau_dmem_migrate_to_ram() on the success path, and
- nouveau_dmem_migrate_copy_one() on the copy-error path.
For an order > 0 folio this unmaps less than was mapped, leaking the
remainder of the IOMMU/IOVA mapping. The other unmap sites, in
nouveau_dmem_migrate_chunk() and nouveau_dmem_evict_chunk(), already
use the saved size; use it here too.
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau: unsubscribe the channel-kill event before the fence context
nouveau_channel_del() tears the fence context down first and only drops
the channel-kill subscription later, in the middle of the nvif object
teardown:
if (chan->fence)
nouveau_fence(chan->cli->drm)->context_del(chan);
...
nvif_object_dtor(&chan->vram);
nvif_event_dtor(&chan->kill);
The subscribed handler is nouveau_channel_killed(), which calls
nouveau_channel_kill() and from there nouveau_fence_context_kill() on
chan->fence. A kill event delivered in that window takes fctx->lock and
walks fctx->pending on a fence context that context_del() has already
freed.
Nothing reaches this below Fermi today, because the subscription is
gated on FERMI_CHANNEL_GPFIFO and nothing kills a channel there. On
Fermi and newer the window is real but narrow, since a kill has to land
exactly while the channel is being destroyed. That is reason enough on
its own, which is why this carries a Fixes: tag. The last patch in this
series subscribes Tesla channels as well; nothing kills those today, so
it does not widen the exposure now, but it is the groundwork for a
recovery path that would, and the ordering is better fixed before that
lands than alongside it.
Drop the subscription before anything it depends on is torn down.
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau/uvmm: fix NULL deref unwinding an OP_MAP_SPARSE op
Each bind_job_op is zeroed by kzalloc_obj() in bind_job_op_from_uop(),
and the OP_MAP_SPARSE case in nouveau_uvmm_bind_job_submit() only creates
a region, so op->ops stays NULL for a successfully processed sparse map.
If a later op in the same job fails, the reverse unwind loop revisits that
op and calls drm_gpuva_ops_free(&uvmm->base, op->ops) unconditionally.
drm_gpuva_ops_free() dereferences its argument right away
(list_for_each_entry_safe on &ops->list), so a NULL op->ops oopses. The
path is reachable by any render-node fd holder, since NOUVEAU_VM_BIND is
DRM_RENDER_ALLOW.
Guard the free with IS_ERR_OR_NULL(), as nouveau_uvmm_bind_job_cleanup()
already does for the identical free.
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau/uvmm: fix premature region free on failed OP_UNMAP_SPARSE
In nouveau_uvmm_bind_job_submit()'s OP_UNMAP_SPARSE arm, op->reg is set
from nouveau_uvma_region_find(), which only looks the region up and takes
no reference; a region's sole reference is its membership in
uvmm->region_mt. Two failure paths leave op->reg set: the -ENOENT check
when the region is busy, and the drm_gpuvm_sm_unmap_ops_create() failure.
The sibling nouveau_uvmm_sm_unmap_prepare() failure just below clears
op->reg; these two do not.
unwind_continue steps back one op, so the failing op is skipped by the
unwind loop and its op->reg stays set. nouveau_uvmm_bind_job_cleanup()
then enters its if (op->reg) branch and calls nouveau_uvma_region_remove()
and nouveau_uvma_region_put() on it, dropping the tree's sole reference
and freeing a region this job never created. The comment above the
cleanup loop documents the broken invariant: op->reg must be NULL on
submit failure.
This frees a live region on an unrelated failure, reachable single-job
when drm_gpuvm_sm_unmap_ops_create() returns -ENOMEM; if another job owns
the same region, its cleanup then removes and puts the freed region, a
use-after-free. Clear op->reg on both failure paths.
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
drm/nouveau/uvmm: clear the dirty flag when unwinding an OP_UNMAP_SPARSE
A successful OP_UNMAP_SPARSE marks its region dirty with
nouveau_uvma_region_dirty() and defers the teardown to
nouveau_uvmm_bind_job_cleanup(); it does not remove the region from
uvmm->region_mt.
If a later op in the job fails, the unwind path never clears reg->dirty
(set in one place, cleared nowhere) and sets op->reg = NULL, so cleanup
skips the teardown. The region is left in the tree with dirty set and its
completion never signalled. Later binds over that range then fail
permanently -- -ENOENT or -EINVAL from the dirty checks, or an unkillable
wait_for_completion() in bind_validate_region() -- for the lifetime of
the uvmm.
Clear reg->dirty when the unwind reverts the sparse unmap, restoring the
region to the state it was found in.
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
bpf: Disable preemption in bpf_get_stackid
The get_perf_callchain call needs disabled preemption plus we need
it disabled as long as we access its returned trace entries buffer.
Note the bpf_get_stackid_pe function is executed already with
preemption disabled.
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
rpcrdma: arm rn_done before publishing the notification
rpcrdma_rn_register() inserts @rn into rd_xa with xa_alloc() before
storing the caller's callback in rn->rn_done. The xarray makes @rn
reachable to rpcrdma_remove_one(), which walks rd_xa and invokes
rn->rn_done(rn) for every registered notification. A device removal
that races a fresh registration can therefore observe @rn with
rn_done still NULL, because the notification objects are zero
allocated by their owners, and call through a NULL function pointer.
Store rn->rn_done before xa_alloc() publishes @rn. The xarray's
store-side and load-side ordering then guarantees that any CPU which
finds @rn in rd_xa also observes the armed callback.
rpcrdma_rn_unregister() treats a non-NULL rn_done as the sentinel
for a completed registration, so the early store must not survive a
failed registration. Clear rn_done again when xa_alloc() fails.
Were it left set, the failed-accept cleanup path would call
rpcrdma_rn_unregister() on an @rn that was never inserted, erasing
an unrelated rd_xa slot and underflowing rd_kref.
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
power: supply: ab8500_fg: fix use-after-free on remove
ab8500_fg_remove() destroys the driver workqueue while the threaded
interrupt handlers are still armed; they are devm-managed and freed
only after ->remove() returns, so a handler that fires in that
window queues work on the freed workqueue.
Tear the workqueue down through devm instead, registering its cleanup
after the power supply and before the interrupt requests. devm then
frees the interrupts first, so the handlers can no longer queue work,
before disabling the delayed and plain work items and destroying the
workqueue. Disabling the items, rather than cancelling them, keeps
them disabled so no producer (including the power-supply
external_power_changed callback) can requeue them.
Found by an in-house static analysis tool.
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/core: avoid infinite kdamond_merge_regions() internal loop
Patch series "mm/damon: unurgent fixes for infinite loop, NULL de-ref and
races", v1.1.
Sashiko found a few issues in DAMON that could cause infinite loop, NULL
dereference and monitoring results degradation. The first two sounds
scary but the infinite loop happens only under unreasonable user setup.
The NULL dereference is only in a unit test. Monitoring results
degradation is trivial since it is only best-effort, and those happens
from only unlikely races. Still those are bugs that better to fix if
possible. Fix those.
This patch (of 6):
Due to online parameter update like events, the number of DAMON regions
could be higher than the user-set upper limit. kdamond_merge_regions()
repeats merge regions until the number meets the limit, while doubling the
merge threshold up to the theoretical maximum threshold. It is tried only
up to the theoretical maximum threshold because even the aggressive
merging can fail from reducing the number of regions under the
user-defined upper limit. For example, there could be many user-defined
non-contiguous regions that cannot be merged.
The threshold based loop break condition is evaluated by comparing the
threshold for the next merging try against the theoretical maximum
threshold. If max_thres is larger than UINT_MAX / 2, doubling the
threshold could make it overflow, and bypass the loop break condition. In
the case, if the number of regions cannot be reduced under the upper limit
like explained above, the loop will run infinitely.
Prevent the case by doing the break condition check before doubling the
threshold. Also, prevent the threshold exceeding the maximum threshold,
as it could overflow and apply the wrong merge threshold.
This issue is unlikely to occur in real world, since having the max_thres
higher than UINT_MAX / 2 require unrealistically large aggregation
intervals compared to the sampling interval. Also, it requires an
unrealistically large number of uncontiguous regions setup. Nonetheless,
the consequence is bad and the fix is simple.
The issue was discovered [1] by Sashiko.
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 8.4
In the Linux kernel, the following vulnerability has been resolved:
PCI: Allow per function PCI slots to fix slot reset on s390
On s390 systems, which use a machine level hypervisor, PCI devices are
always accessed through a form of PCI pass-through which fundamentally
operates on a per PCI function granularity. This is also reflected in the
s390 PCI hotplug driver which creates hotplug slots for individual PCI
functions. Its reset_slot() function, which is a wrapper for
zpci_hot_reset_device(), thus also resets individual functions.
Currently, the pci_create_slot() assigns the same pci_slot object to
multifunction devices. This approach worked fine on s390 systems that only
exposed virtual functions as individual PCI domains to the operating
system. Since commit 44510d6fa0c0 ("s390/pci: Handling multifunctions")
s390 supports exposing the topology of multifunction PCI devices by
grouping them in a shared PCI domain. This creates a problem when resetting
a function through the hotplug driver's slot_reset() interface.
When attempting to reset a function through the hotplug driver, the shared
slot assignment causes the wrong function to be reset instead of the
intended one. It also leaks memory as we do create a pci_slot object for
the function, but don't correctly free it in pci_slot_release().
Add a flag for struct pci_slot to allow per function PCI slots for
functions managed through a hypervisor, which exposes individual PCI
functions while retaining the topology. Since we can use all 8 bits for
slot 'number' (for ARI devices), change slot 'number' u16 to account for
special values PCI_SLOT_PLACEHOLDER and PCI_SLOT_ALL_DEVICES.
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: zero pipe read compound padding
Compound response handling extends the last response iov to an eight-byte
boundary.
smb2_read_pipe() allocates only the payload size, so the alignment padding
can expose up to seven bytes of uninitialized kernel heap memory.
Allocate the aligned size and clear the unused tail before pinning the
response buffer.
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
ublk: clear VM_MAYWRITE on read-only ublk char device mmap
ublk_ch_mmap() rejects mmap requests with VM_WRITE set, but never
clears VM_MAYWRITE on the resulting read-only mapping. This allows
a userspace daemon to mmap the per-queue command buffer PROT_READ,
then upgrade it to PROT_WRITE via mprotect(), since VM_MAYWRITE was
never cleared.
The command buffer holds struct ublksrv_io_desc entries that are
kernel-written ABI; a writable mapping lets an unprivileged daemon
process corrupt fields such as addr, op_flags, nr_sectors, and
start_sector.
Same bug class as the drm/panthor and drm/vc4 VM_MAYWRITE fixes, and
the 2026-08-13 ptp/vmclock fix (a5edadbae57e).
Verified via mprotect() PoC: before the fix, a PROT_READ mapping can
be upgraded to PROT_READ|PROT_WRITE and a write into the command
buffer corrupts io_desc fields (confirmed under KASAN). After the
fix, mprotect() returns -EACCES.
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 7.1
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: prevent out-of-bounds reads in share config responses
Validate IPC share configuration payload sizes before consuming
variable-length fields. Bound veto list parsing and account for
the separator byte when deriving the path length.
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
perf: Fix use-after-free when perf mmap() revival races with the last munmap()
perf_mmap_close() drops rb->mmap_count *without* holding
event->mmap_mutex (the refcount_dec_and_test() right before the
refcount_dec_and_mutex_lock() of event->mmap_count). A concurrent
perf_mmap_rb() can slot its entire "revival" path into that window
(perf_mmap holds event->mmap_mutex for its whole duration, including
rb_alloc):
munmap side (perf_mmap_close) mmap side (perf_mmap_rb)
----------------------------------- --------------------------------
rb->mmap_count 1 -> 0 (no lock) (holds event->mmap_mutex)
inc_not_zero(rb->mmap_count) fails
ring_buffer_attach(event, NULL)
rb_alloc() + attach new rb
refcount_set(&event->mmap_count, 1)
lock; event->mmap_count 1 -> 0
ring_buffer_attach(event, NULL)
ring_buffer_put() -> frees the *new* rb
The revival's refcount_set(&event->mmap_count, 1) is an invisible
1 -> 1 write: the close frees the just-revived buffer although the
other process still has it mapped -- a page-level use-after-free
allowing local privilege escalation to root by any unprivileged user
(default kernel.perf_event_paranoid=2).
Swap the order of the two counter updates: event->mmap_count is
dropped first via refcount_dec_and_mutex_lock(), so its 1 -> 0
transition and the ring_buffer_attach() stay serialized with
perf_mmap(). rb->mmap_count == 0 then implies every event using the
buffer is detached already, so the result of the rb->mmap_count drop
can gate the remaining teardown directly and detach_rest is no longer
needed.
An earlier fix for this race from Kyle Zeng and David Lee takes
event->mmap_mutex around both counter updates [0]; here the not-last
close stays lockless.
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
ipv6: avoid divide by zero in rt6_multipath_rebalance
rt6_multipath_rebalance() calculates the total eligible nexthop weight
in one pass and programs upper bounds in a second pass. Since
RTM_NEWROUTE is RTNL-free, a concurrent
ignore_routes_with_linkdown update can make the first pass return zero
while the second sees an eligible nexthop, causing
rt6_upper_bound_set() to divide by zero.
UBSAN: division-overflow in net/ipv6/route.c:4845:17
Oops: divide error: 0000 [#1] SMP KASAN NOPTI
rt6_upper_bound_set() net/ipv6/route.c:4845
rt6_multipath_rebalance()
fib6_add_rt2node()
ip6_route_multipath_add()
inet6_rtm_newroute()
Skip upper-bound calculation when the first pass reports a zero total.
This respects the lock-free performance considerations here and solves
insecure scenarios.
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
gtp: add synchronize_net() in gtp_newlink() error path to prevent use-after-free
gtp_newlink()'s error path frees tid_hash and addr_hash without
waiting for an RCU grace period after clearing sk_user_data. A
concurrent gtp_encap_recv() in softirq may still hold the gtp_dev
pointer obtained via rcu_dereference_sk_user_data() and access the
freed memory.
BUG: KASAN: slab-use-after-free in gtp0_pdp_find+0x1f6/0x200 (gtp.c:152)
Call Trace:
<IRQ>
gtp0_pdp_find+0x1f6/0x200
gtp_encap_recv+0x527/0x24b0
udp_queue_rcv_one_skb+0x75f/0xc10
Add synchronize_net() before the kfree calls in out_hashtable, which
covers all error paths from both gtp_encap_enable() and
gtp_create_sockets().
Published Sep 16, 2026 · Updated Oct 19, 2026
Critical · CVSS 9.8
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix tree connection use-after-free in smb2_tree_connect()
ksmbd_tree_conn_connect() publishes a new tree connection in
sess->tree_conns with a single reference and returns its pointer to
smb2_tree_connect(). The handler continues to initialize the object and
build the response after publication. A concurrent session logoff can
erase the connection and drop that reference, freeing the object while
the handler still uses it.
BUG: KASAN: slab-use-after-free in smb2_tree_connect+0xe3d/0xf90
smb2_tree_connect (fs/smb/server/smb2pdu.c:2872)
handle_ksmbd_work
process_one_work
worker_thread
kthread
After xa_store() succeeds, take a second reference before releasing
tree_conns_lock. The original reference belongs to the xarray entry and
the second belongs to the creating smb2_tree_connect() handler.
Keep the references balanced in every path:
- On normal exit or an error after publication, smb2_tree_connect()
drops its creator reference. Error cleanup also calls
ksmbd_tree_conn_disconnect(), which drops the xarray reference only if
it removes the exact entry.
- SMB2 TREE_DISCONNECT uses the same helper to remove the entry and drop
its xarray reference. The request's existing lookup reference remains
owned by the request and is released by the existing cleanup.
- Session LOGOFF removes each entry and drops its xarray reference. If
it wins the race, later cleanup sees that the entry is gone and does
not drop that reference again.
To enforce this ownership, claim the disconnected state and erase the
exact entry atomically under tree_conns_lock. This guarantees one drop
for the xarray reference and one drop by each in-flight user, regardless
of which teardown path wins. If logoff removes the entry before
initialization completes, fail the connect instead of marking the
detached object TREE_CONNECTED.
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
ext4: check dir entry fits before reading the hash trailer in ext4_search_dir()
For casefolded encrypted directories ext4 stores an 8-byte hash trailer
after the name (EXT4_DIRENT_HASHES()), at an offset derived from
de->name_len. On the sb_no_casefold_compat_fallback() path ext4_match()
reads that trailer, but ext4_search_dir()'s by-hand pre-check only tests
de->name + de->name_len <= dlimit, which proves the name fits, not the
rounded trailer. A crafted entry whose name ends at the block boundary
passes the check while EXT4_DIRENT_HASHES(de) lands past the block end,
so ext4_match() reads out of bounds on an ordinary lookup. KASAN reports
it as a use-after-free when the page after the directory block holds a
freed object:
BUG: KASAN: use-after-free in ext4_match (fs/ext4/namei.c:1435)
Read of size 4 at addr ffff888010458000 by task exploit
Call Trace:
ext4_match (fs/ext4/namei.c:1435)
ext4_search_dir (fs/ext4/namei.c:1470)
__ext4_find_entry (fs/ext4/namei.c:1268 fs/ext4/namei.c:1632)
ext4_lookup (fs/ext4/namei.c:1703 fs/ext4/namei.c:1769)
...
filename_lookup (fs/namei.c:2842)
vfs_statx (fs/stat.c:353)
__do_sys_newfstatat (fs/stat.c:538)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Require, for hash-in-dirent directories, that the whole entry including
the rounded trailer fits before calling ext4_match(). This is the same
bound ext4_check_dir_entry() already enforces via ext4_dir_rec_len(), so
no well-formed entry is rejected. The other caller, ext4_find_dest_de(),
runs ext4_check_dir_entry() first and is unaffected.
Published Sep 16, 2026 · Updated Oct 19, 2026
Critical · CVSS 9.1
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix out-of-bounds read in ext4_read_inline_dir()
ext4_read_inline_dir() can read a dirent header past the end of its inline
buffer, triggering a slab-out-of-bounds read during getdents64():
BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry
Read of size 2 at addr ffff88800f3dd23c by task exploit/148
...
__ext4_check_dir_entry
ext4_read_inline_dir
iterate_dir
The dirent payload lives in a buffer of exactly inline_size bytes:
dir_buf = kmalloc(inline_size, GFP_NOFS);
but iteration runs in a position space extra_offset bytes larger
(extra_size = extra_offset + inline_size) so the synthetic "." and ".."
land at their block-dir offsets. A dirent is formed at "dir_buf + pos -
extra_offset", yet the ext4_check_dir_entry() length argument uses the
larger extra_size. A position whose dirent header would extend past
extra_size is therefore accepted, and the rescan loop's rec_len probe and
ext4_check_dir_entry() dereference de->rec_len before the entry is rejected.
Reject a position whose minimum-size dirent header would not fit within
extra_size before forming de, in both the rescan and main loops, and pass
inline_size rather than extra_size to ext4_check_dir_entry() so the length
check matches the physical buffer.
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: fix out-of-bounds read of INDEX_ROOT in reparse/objid init
ntfs_reparse_init() and ntfs_objid_init() parse the index root of the
$Extend/$Reparse and $Extend/$ObjId metafiles (the INDEX_ROOT attributes
named $R and $O). They read its type and rule fields through
resident_data(), which does not check that the resident attribute is
large enough to hold them.
mi_enum_attr() accepts a resident attribute with data_off == asize and
data_size == 0. For such an attribute placed last in its MFT record,
resident_data() returns a pointer to the end of the record_size buffer,
so reading root->type / root->rule reads past the allocation.
Use resident_data_ex(attr, sizeof(struct INDEX_ROOT)) and bail out when
it returns NULL, as ntfs_security_init() already does for $SDH / $SII.
The attribute is only parsed while mounting a crafted image, so this
needs CAP_SYS_ADMIN.
BUG: KASAN: slab-out-of-bounds in ntfs_reparse_init (fs/ntfs3/fsntfs.c:2306)
Read of size 4 at addr ffff88801219dc00 by task mount
ntfs_reparse_init (fs/ntfs3/fsntfs.c:2306)
ntfs_fill_super (fs/ntfs3/super.c:1604)
get_tree_bdev_flags (fs/super.c:1703)
vfs_get_tree (fs/super.c:1758)
path_mount (fs/namespace.c:4131)
__x64_sys_mount (fs/namespace.c:4360)
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6
rpcb_register_inet4() and rpcb_register_inet6() store the result of
rpc_sockaddr2uaddr() into map->r_addr without checking it for NULL.
rpc_sockaddr2uaddr() returns NULL when its final kstrdup() fails, and
the unchecked NULL is then carried into the synchronous RPCBPROC_SET
encode path: rpcb_register_call() -> rpc_call_sync() ->
rpcb_enc_getaddr() -> encode_rpcb_string(), whose first statement is
strlen(string), dereferencing NULL and oopsing the kernel.
The crash reproduces under failslab on v6.12; with KASAN the NULL
dereference surfaces as a fault on the shadow of address zero:
Oops: general protection fault, probably for non-canonical address
0xdffffc0000000000 [#1] PREEMPT SMP KASAN
RIP: 0010:strlen (lib/string.c:409)
Call Trace:
encode_rpcb_string (net/sunrpc/rpcb_clnt.c:890)
rpcb_enc_getaddr (net/sunrpc/rpcb_clnt.c:910)
rpcauth_wrap_req_encode (net/sunrpc/auth.c:745)
call_encode (net/sunrpc/clnt.c:1966)
__rpc_execute (net/sunrpc/sched.c:952)
rpc_run_task (net/sunrpc/clnt.c:1243)
rpc_call_sync (net/sunrpc/clnt.c:1272)
rpcb_v4_register (net/sunrpc/rpcb_clnt.c:500)
svc_generic_rpcbind_set
nfsd_rpcbind_set
svc_register
svc_setup_socket
svc_addsock
write_ports
nfsctl_transaction_write
vfs_write
The crash is reachable when an in-kernel RPC service (nfsd, lockd,
nfs-callback) registers with the local rpcbind under enough memory
pressure for the small GFP_KERNEL kstrdup() in rpc_sockaddr2uaddr() to
fail. The asynchronous getport path already handles this exact failure
mode by returning -ENOMEM; only the two register helpers omit the check.
Mirror that handling: bail out with -ENOMEM when rpc_sockaddr2uaddr()
returns NULL, before the address is fed into the encoder.
Published Sep 16, 2026 · Updated Oct 19, 2026
Critical · CVSS 9.8
In the Linux kernel, the following vulnerability has been resolved:
xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full
The depth check in xfrm6_input_addr() is off by one:
if (1 + sp->len == XFRM_MAX_DEPTH)
goto drop;
...
sp->xvec[sp->len++] = x;
xfrm_input() can leave sp->len == XFRM_MAX_DEPTH, and the transport-mode
receive path re-enters IPv6 input via xfrm_trans_reinject() with that
secpath preserved. If the inner packet carries a destination-options HAO
option or a type-2 routing header, xfrm6_input_addr() is called with
sp->len == XFRM_MAX_DEPTH; the check (1 + 6 == 6) is false, so
sp->xvec[sp->len++] writes one slot past the 6-element xvec[]. The write
stays within the sec_path allocation (invisible to KASAN); UBSAN_BOUNDS
flags it and panics under panic_on_warn.
Use "sp->len >= XFRM_MAX_DEPTH", matching xfrm_input(). This also
restores one chain level the old check rejected at sp->len == 5.
UBSAN: array-index-out-of-bounds in net/ipv6/xfrm6_input.c:309:10
index 6 is out of range for type 'xfrm_state *[6]'
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 8.4
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: reject restart table growth beyond U16_MAX entries
During $LogFile replay, log_replay() indexes the transaction table by the
transact_id taken from the log record header. check_log_rec() only
verifies that transact_id is non-zero and properly aligned, not its
magnitude, so a crafted image can request an arbitrarily large index.
alloc_rsttbl_from_idx() grows the table to cover that index via
extend_rsttbl(), which passes the new entry count to init_rsttbl():
rt = init_rsttbl(esize, used + add);
used + add is computed as u32 but init_rsttbl() takes a u16, and the
count is stored in struct RESTART_TABLE as a __le16. When used + add
exceeds U16_MAX it is truncated, init_rsttbl() allocates a table far
smaller than the index requires, and alloc_rsttbl_from_idx() then
dereferences and writes at the original, untruncated offset -- an
out-of-bounds access past the allocation, reachable by mounting a
crafted NTFS image.
BUG: KASAN: use-after-free in alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950)
Read of size 4 at addr ffff8880327ffff8 by task exploit
alloc_rsttbl_from_idx (fs/ntfs3/fslog.c:950)
log_replay (fs/ntfs3/fslog.c:4562)
ntfs_loadlog_and_replay (fs/ntfs3/fsntfs.c:324)
ntfs_fill_super (fs/ntfs3/super.c:1393)
get_tree_bdev_flags
vfs_get_tree
path_mount
__x64_sys_mount
A restart table is limited to U16_MAX entries by its __le16 count, so a
larger growth request is invalid input. Reject it in extend_rsttbl();
all callers already handle a NULL return.
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 8.4
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: fix out-of-bounds read in read_log_rec_buf()
read_log_rec_buf() copies a log record into a caller buffer starting at
u32 off = lsn_to_page_off(log, lsn) + log->record_header_len;
log->record_header_len (and log->data_off, used for the following pages)
comes verbatim from the on-disk restart area and is only checked for
8-byte alignment in is_rst_area_valid(), so off can exceed
log->page_size. "tail = log->page_size - off" then underflows and
memcpy() reads past the page_size-sized buffer returned by
read_log_page(), spilling adjacent slab memory into the replay buffer.
This is reachable by mounting a crafted NTFS image:
BUG: KASAN: slab-out-of-bounds in read_log_rec_buf+0x216/0x580
Read of size 64 at addr ffff88800a877ff8 by task exploit/127
read_log_rec_buf fs/ntfs3/fslog.c:2299
log_replay fs/ntfs3/fslog.c:4216
ntfs_loadlog_and_replay fs/ntfs3/fsntfs.c:324
ntfs_fill_super fs/ntfs3/super.c:1392
get_tree_bdev_flags fs/super.c:1694
__x64_sys_mount fs/namespace.c:4360
The buggy address is located 4088 bytes to the right of
the 4096-byte region [ffff88800a876000, ffff88800a877000)
Reject an in-page offset outside the current page before the copy.
[almaz.alexandrovich@paragon-software.com: replaced the >= sign with >]
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
net: qualcomm: rmnet: restore skb->dev on deaggregated frames
rmnet_map_deaggregate() allocates each sub-frame with alloc_skb() and
leaves skb->dev NULL. __rmnet_map_ingress_handler() assigns
skb->dev = ep->egress_dev only on the data path, but a MAP command frame
is dispatched to rmnet_map_command() before that, so rmnet_map_send_ack()
runs netif_tx_lock(skb->dev) on a NULL device. An unprivileged user
reaches this by unsharing a user+net namespace, creating an rmnet link
over a tap device with INGRESS_DEAGGREGATION and INGRESS_MAP_COMMANDS,
and writing an aggregated frame carrying a flow-control command to the
tap fd.
Restore the assignment dropped by 378e25357ac7, so every skb leaving
rmnet_map_deaggregate() has a valid device.
BUG: KASAN: null-ptr-deref in _raw_spin_lock (kernel/locking/spinlock.c:158)
Write of size 4 at addr 00000000000004b4 by task exploit/144
Call Trace:
_raw_spin_lock (kernel/locking/spinlock.c:158)
netif_tx_lock (net/sched/sch_generic.c:497)
rmnet_map_command (drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c:67)
rmnet_rx_handler (drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c:125)
__netif_receive_skb_core.constprop.0 (net/core/dev.c:6103)
...
__netif_receive_skb_one_core (net/core/dev.c:6214)
netif_receive_skb (net/core/dev.c:6474)
tun_get_user (drivers/net/tun.c:1966)
tun_chr_write_iter (drivers/net/tun.c:2012)
vfs_write (fs/read_write.c:687)
ksys_write (fs/read_write.c:739)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Kernel panic - not syncing: Fatal exception in interrupt
Published Sep 16, 2026 · Updated Oct 19, 2026
Critical · CVSS 9.1
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: validate ef->size covers the record's name and value
When an EA record has a non-zero ef->size, ntfs_read_ea() only checks
that the record fits in the remaining buffer (ea_size > bytes), not that
ef->size is large enough to hold the record's own name_len + 1 + elength.
A crafted image can pass validation with, e.g., ef->size = 24 but
elength = 0xffff. ntfs_get_ea() then trusts elength and copies it out of
the undersized record, reading past the kmalloc(info->size) allocation
and leaking heap memory to userspace via getxattr():
BUG: KASAN: slab-out-of-bounds in ntfs_get_ea (fs/ntfs3/xattr.c:302)
Read of size 65535 at addr ffff888100794550 by task exploit
__asan_memcpy (mm/kasan/shadow.c:105)
ntfs_get_ea (fs/ntfs3/xattr.c:302)
ntfs_getxattr (fs/ntfs3/xattr.c:848)
__vfs_getxattr (fs/xattr.c:441)
vfs_getxattr (fs/xattr.c:474)
do_getxattr (fs/xattr.c:800)
path_getxattrat (fs/xattr.c:868)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
The buggy address is located 80 bytes inside of
allocated 84-byte region in cache kmalloc-96
Compute the size the record needs and require ef->size to cover it.
Published Sep 16, 2026 · Updated Oct 19, 2026
Critical · CVSS 9.8
In the Linux kernel, the following vulnerability has been resolved:
isofs: fix out-of-bounds page array access on empty zisofs block
zisofs_uncompress_block()'s empty-block fast path returns
pcount << PAGE_SHIFT, ignoring the incoming poffset, unlike the
decompression path which returns bytes produced relative to poffset.
zisofs_fill_pages() uses that return to advance its page cursor, so when
the zisofs block size is below PAGE_SIZE and a sub-page block leaves
poffset partway into a page, a following empty block over-counts and
advances pages[] one element past its end, after which
"if (poffset && *pages)" reads pages[1] out of bounds. rock.c only
rejects a block-size shift > 17, so a crafted "ZF" Rock Ridge record can
set it below PAGE_SHIFT; the bug is reached by an ordinary read() of a
compressed file on such a mounted ISO9660 image.
Return the byte count relative to poffset and zero only
[poffset, PAGE_SIZE) of the first page, matching the decompression path.
The page-aligned case (poffset == 0) is unaffected.
BUG: KASAN: slab-out-of-bounds in zisofs_read_folio (fs/isofs/compress.c:290)
Read of size 8 at addr ffff88800f5eac48 by task exploit/142
zisofs_read_folio (fs/isofs/compress.c:290)
read_pages (mm/readahead.c:184)
...
filemap_read (mm/filemap.c:2814)
vfs_read (fs/read_write.c:574)
__x64_sys_pread64 (fs/read_write.c:769)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
The buggy address is located 0 bytes to the right of the
allocated 8-byte region in the kmalloc-8 cache
Published Sep 16, 2026 · Updated Oct 19, 2026
High · CVSS 8.8
In the Linux kernel, the following vulnerability has been resolved:
vfio/pci: clear vdev->msi_perm after freeing it on init failure
vfio_msi_cap_len() lazily allocates the per-device MSI permission table:
vdev->msi_perm = kmalloc_obj(struct perm_bits, GFP_KERNEL_ACCOUNT);
if (!vdev->msi_perm)
return -ENOMEM;
ret = init_pci_cap_msi_perm(vdev->msi_perm, len, flags);
if (ret) {
kfree(vdev->msi_perm);
return ret; /* vdev->msi_perm left dangling */
}
When init_pci_cap_msi_perm() -> alloc_perm_bits() fails with -ENOMEM, the
error path frees vdev->msi_perm but leaves the freed pointer stored in
it. vdev->msi_perm is not re-zeroed later because struct
vfio_pci_core_device is per-device and persists across open/close cycles,
and the vfio_config_init() error path returns without calling
vfio_config_free(). So the dangling pointer outlives the failed open.
That leads to two use-after-frees on the same device:
1. Reuse. The next vfio_config_init() sees the stale pointer at
"if (vdev->msi_perm) return len;" and reuses the freed object. MSI
config accesses in vfio_pci_config_rw_single() then dereference and
call the freed perm->readfn / perm->writefn function pointers.
2. Double free. A later vfio_config_free() runs free_perm_bits() and
kfree() on the already-freed object.
Fix it by NULLing vdev->msi_perm after the kfree(), matching the
NULL-after-free discipline already used in free_perm_bits() and
vfio_config_free().
BUG: KASAN: slab-use-after-free in vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)
Read of size 8 at addr ffff88800fcc88d0 by task exploit/143
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)
vfio_pci_config_rw (drivers/vfio/pci/vfio_pci_config.c:1986)
vfio_pci_rw (drivers/vfio/pci/vfio_pci_core.c:1599)
vfs_read (fs/read_write.c:572)
__x64_sys_pread64 (fs/read_write.c:764)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
...
Followed on device close by a double free of the same object:
Oops: general protection fault, probably for non-canonical address
0x1f63e0e8000008: 0000 [#1] SMP KASAN NOPTI
RIP: 0010:kfree (mm/slub.c:6711)
Call Trace:
vfio_config_free (drivers/vfio/pci/vfio_pci_config.c:1861)
vfio_pci_core_disable (drivers/vfio/pci/vfio_pci_core.c:685)
vfio_pci_core_close_device (drivers/vfio/pci/vfio_pci_core.c:777)
vfio_df_close (drivers/vfio/vfio_main.c:602)
vfio_device_fops_release (drivers/vfio/vfio_main.c:648)
__fput (fs/file_table.c:512)
__x64_sys_close (fs/open.c:1496)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
...
Kernel panic - not syncing: Fatal exception
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
vxlan: vnifilter: enforce exact length of GROUP/GROUP6 attributes
The VXLAN VNI filter entry policy declares the GROUP/GROUP6 address
attributes as NLA_BINARY with only a maximum length, so validate_nla()
accepts a payload shorter than the address. The GROUP consumer reads it
with nla_get_in_addr(), an unconditional 4-byte load, so a short
attribute over-reads up to 3 bytes of uninitialised slab data, which are
stored into remote_ip and echoed back via RTM_GETTUNNEL, disclosing
kernel memory.
Switch both entries to NLA_POLICY_EXACT_LEN() so the validator rejects
any GROUP/GROUP6 that is not exactly 4 / 16 bytes; a valid address is
always sent at full width.
Published Sep 16, 2026 · Updated Oct 19, 2026
Critical · CVSS 9.3
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Handle negative S1 walk levels in VNCR TLB size evaluation
Computing the effects of a TLB invalidation involves looking at
the size of the mapping cached by the TLB. For S1 mappings such as
VNCR, this is deducted from the combination of the base granule size
and the mapping level.
However, this implies that the S1 MMU is *on*. When the MMU is off,
we indicate this with the level being set to a "creative" value of
-127 (S1_MMU_DISABLED).
This ends-up being misinterpreted by pgshift_level_to_ttl() as it
doesn't handle negative levels at all (the level is immediately cast
to a u8 and only the bottom two bits considered), leading to an
invalidation size of 0. Not helpful.
Tidy-up pgshift_level_to_ttl() to handle these negative levels, and
ttl_to_size() to always return SZ_1G when no valid TTL is present.
This allows the removal of open-coded checks for similar situations.
Note that the check for a negative value not explicitely checking for
S1_MMU_DISABLED is deliberate, so that actual negative levels introduced
with LVA2 and D128 can take the same path if we ever support them.
Published Sep 16, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Skip Update HDCP Config In Transition State
Transition state does not have a valid dm_stream_ctx that should skip
configuring HDCP routine. The routine is valid to go through only when
a valid stream is created.
Published Sep 11, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
btrfs: write-protect folios during data writeback
commit 095be159f3eb ("btrfs: unify folio dirty flag clearing") replaced
the folio_clear_dirty_for_io() call in extent_write_cache_pages() with a
plain folio_test_dirty() check. Besides clearing the dirty flag,
folio_clear_dirty_for_io() also calls folio_mkclean(), which write-protects
the shared mmap PTEs mapping the folio. Note that we still do call
folio_clear_dirty_for_io() later in submit_one_sector() when we clear
dirty on the last sector of the folio (the only sector for non-subpage
cases). But we lost this early call in extent_write_cache_pages().
Without the extra write-protection, a process with the file mmap-ed can
modify a sector while it is being used by writeback in a way that
expects a stable folio (checksumming, compressing, copying, etc...)
without faulting, which manifests as a handful of concrete bugs.
1. For large folios or subpage sectorsize, it is possible to submit a bio
which does not cover the whole folio. When this happens, we will have a
bio in flight for a folio that we have *not* called
folio_clear_dirty_for_io() on. If a task with an existing mmap-ed PTE
writes (without faulting..) in this window, it can result in
corruptions. If the write arrives while the checksumming or writing itself
is underway, this can result in an invalid checksum and later corruption
reports on read. If the write arrives after checksumming/writing is done
but before the last sector dirty is cleared, then the write is present
in page cache but doesn't affect the dirty tracking and will be lost
when the folio is fully finished being submitted and the dirty bit
is cleared. This results in losing the write even if fsync() is called.
2. For zoned submissions which are done in batch separate from the main
extent_writepage() loop, we also risk csum violations for those
submissions. Zoned writes are clamped to max_zone_append_size and are
not aligned with folios, so a submission can span two folios. The first
folio being processed in extent_write_cache_pages() will call
extent_write_locked_range() which will submit the partial range of the
next folio, while the rest of that folio could still be dirty. So
clearing dirty on the submitted sectors doesn't call
folio_clear_dirty_for_io() and we have the same issue. Since
extent_write_cache_pages() skips these batch submitted folios (they are
already marked for writeback from submission by the preceding folio), we
must add the extra write protection in lock_delalloc_folios().
3. For inline extents this will subtly risk losing writes that happen
after/while we copy the inline extent but before we clear dirty on
the folio.
4. For folios spanning EOF, mmap could tamper with the zeroed bytes past
EOF and cause them to be persisted where future faults would improperly
see them instead of zeros.
5. Finally, for compressed extents, we risk modifying the folios while we
work on compressing them which will result in corrupted compressed data.
Specifically, in run_delalloc_compressed() we queue up work to do
compress_file_range() in BTRFS_COMPRESSION_CHUNK_SIZE (512K) chunks which
will call btrfs_folio_clamp_clear_dirty() on the range. For non-subpage,
this will always clear the whole folio, safely. For subpage, we risk a
partial clear here as well. In particular, imagine a 2M folio broken up
into 512K chunks of work which might start compression work on one chunk
before all the chunks compress_file_range() workers have gotten far
enough to finish clearing all the dirty bitmaps of the folio and getting
to folio_clear_dirty_for_io(). Large folios on the edges of submission
ranges are similarly at risk to be only partly cleared.
This particular gap was introduced by a second patch in the same series:
commit a4ef54dbb576 ("btrfs: make extent_range_clear_dirty_for_io() to handle sector size < page size cases")
We cannot simply restore the call to folio_clear
---truncated---
Published Sep 11, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Fix subbuf resize race with ring buffer readers
trace_buffer subbuf_size is read lockless in ring_buffer_read_page() and
ring_buffer_read_start(), while it can simultaneously be resized with
ring_buffer_subbuf_order_set().
Instead of trace_buffer::subbuf_size, use bpage::order in
ring_buffer_read_start() and ring_buffer_read_page().
In ring_buffer_read_start(), even with resize_disabled, there is still a
possibility of a race with a buffer modification. Hold the trace_buffer
mutex to synchronise with any pending ring buffer order modification.
trace_buffer::subbuf_size is now actually useless, remove it. Also,
create accessors rb_subbuf_capacity() and rb_page_capacity() which
return the actual size available for storing events, while
rb_subbuf_size() returns the actual subbuf page-size.
Published Sep 11, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
iomap: don't free integrity payload that doesn't exist
fs_bio_integrity_alloc might not allocate a bio integrity payload if PI
verification is disabled on the block device. Check for that case before
calling fs_bio_integrity_free in iomap_bio_read_folio_range_sync to
avoid a NULL pointer dereferences.
Make the branch cover the PI verification as well - while
fs_bio_integrity_verify works without an integrity payload, it requires
one to actually do useful work.
Published Sep 11, 2026 · Updated Oct 19, 2026
High · CVSS 7.4
In the Linux kernel, the following vulnerability has been resolved:
clocksource/drivers/nxp-pit: Fix IRQ leak on cpuhp_setup_state error path
When cpuhp_setup_state fails after pit_clockevent_per_cpu_init has
successfully called request_irq, the error handling jumps directly to
out_pit_clocksource_unregister without freeing the registered IRQ.
This leaks the IRQ line and, since kfree(pit) follows, leaves a
dangling pointer registered as the interrupt handler's dev_id,
potentially leading to a use-after-free if the IRQ fires afterwards.
Fix it by calling pit_clockevent_per_cpu_exit to properly release the
IRQ before falling through to the existing cleanup chain.
Published Sep 11, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
fs: fix user path of nested backing files
backing_file_open() derives the path to be stored in the new backing
file from user_file->f_path. This is incorrect when user_file itself
is a backing file, which is the case for nested stacking filesystems,
e.g. overlayfs mounts where the lowerdir of one overlayfs is the merged
directory of another. Since commit def3ae83da02 ("fs: store real path
instead of fake path in backing file f_path") the f_path of a backing
file holds the real path of the intermediate layer, not the path that
the user opened.
Commit 924577e4f6ca ("ovl: Fix nested backing file paths") fixed this
for such configurations by passing file_user_path() from
ovl_open_realfile(). However, commit 6af36aeb147a ("lsm: add
backing_file LSM hooks") changed the first argument of
backing_file_open() from the user path back to the user file and
derived the path from user_file->f_path again, silently re-introducing
the problem.
As a result, files mapped through a nested overlayfs show the wrong
path in /proc/<pid>/maps and in perf/ftrace mmap records. For example,
with two nested overlayfs mounts:
mkdir -p /ovl/{lower,upper,work,merged} /ovl/nested
echo hello > /ovl/lower/foo
mount -t overlay overlay \
-o lowerdir=/ovl/lower,upperdir=/ovl/upper,workdir=/ovl/work \
/ovl/merged
# at least two lowerdirs are needed when upperdir is nonexistent
mount -t overlay overlay \
-o lowerdir=/ovl/merged:/ovl/lower /ovl/nested
mapping /ovl/nested/foo shows a disconnected path instead of the user
path:
# readlink /proc/self/fd/3
/ovl/nested/foo
# grep foo /proc/self/maps
7f6e2c100000-7f6e2c101000 r--s 00000000 00:24 15813027 /foo
The bogus path is derived from the f_path of the intermediate backing
file, whose mount is a private clone that d_path() cannot resolve.
Fix this by using file_user_path(), which returns the outermost
user-visible path for backing files and falls back to
&user_file->f_path for regular files. This restores the behavior of
commit 924577e4f6ca ("ovl: Fix nested backing file paths") for
overlayfs and also fixes the same problem for the other
backing_file_open() callers, fuse passthrough and erofs ishare, when
their user file is itself a backing file.
backing_tmpfile_open() has the same pattern but is not affected: it is
only called by ovl_create_tmpfile() for the upper layer, and another
overlayfs is rejected as upperdir by the DCACHE_OP_REAL check in
ovl_mount_dir_check(), so its user_file can never be a backing file.
Published Sep 11, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
ovl: fix double end_creating() on the casefold-mismatch path
ovl_create_real() releases the new dentry twice when the casefold
consistency check fails. The S_IFDIR branch calls end_creating() and
sets err, then falls through to the common out: label which calls
end_creating() on the same dentry again:
case S_IFDIR:
newdentry = ovl_do_mkdir(ofs, dir, newdentry, attr->mode);
err = PTR_ERR_OR_ZERO(newdentry);
if (!err && ofs->casefold != ovl_dentry_casefolded(newdentry)) {
pr_warn_ratelimited(...);
end_creating(newdentry); /* first */
err = -EINVAL;
}
break;
...
if (err)
goto out;
...
out:
if (err) {
end_creating(newdentry); /* second, same dentry */
return ERR_PTR(err);
}
end_creating() is end_dirop(), which does inode_unlock() on the parent
and dput() on the dentry, so the parent directory's i_rwsem is unlocked
twice and the dentry is put twice. The second unlock releases a lock
that is not held, which is what wedges every later creation under that
parent, and the second dput() drops a reference that was never taken.
The branch was added by commit dfc7da402ccc ("ovl: Check for casefold
consistency when creating new dentries") as a bare dput(), which already
released the reference twice; commit fe497f0759e0 ("VFS: change
vfs_mkdir() to unlock on failure.") converted both sites to
end_creating(), adding the double unlock.
This is reachable by an unprivileged user. The casefold consistency of
the layers is validated at mount time in ovl_parse_layer(), and again on
every lookup in ovl_lookup_single(), but ofs->workdir is the internal
"work" subdirectory created inside the user-supplied workdir, and that
subdirectory is not re-checked. Marking it casefolded after the mount
therefore makes every ovl_create_temp() inherit the wrong state - and
that path reaches ovl_create_real() through ovl_start_creating_temp(),
which uses start_creating() with a generated name and so never runs the
lookup-time check.
unshare -Urm
mount -t tmpfs -o casefold=utf8-12.1.0 tmpfs mnt
mkdir -p mnt/lower/d mnt/upper mnt/work mnt/merged
mount -t overlay ovl -o lowerdir=mnt/lower,\
upperdir=mnt/upper,workdir=mnt/work mnt/merged
chattr +F mnt/work/work
mkdir mnt/merged/d/sub # directory copy-up
overlayfs: wrong inherited casefold (work/#5)
and the next copy-up blocks forever on the parent's i_rwsem:
mkdir D start_creating+0x65/0xb0
ovl_start_creating_temp+0xb0/0xe0 [overlay]
ovl_create_temp+0xa3/0x1d0 [overlay]
ovl_copy_up_one+0x1f1c/0x21c0 [overlay]
ovl_copy_up_flags+0xf5/0x140 [overlay]
ovl_create_object+0xb7/0x220 [overlay]
ovl_mkdir+0x23/0x40 [overlay]
Drop the end_creating() from the branch and let out: own the cleanup,
which is what every other error path in this function already does.
Published Sep 11, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
pidfd: hold exec_update_lock around namespace ioctl
The PIDFD_GET_*_NAMESPACE ioctls in pidfd_ioctl() perform a filesystem
credentials ptrace access check before handing out a namespace file
descriptor. The accompanying comment states that the code "mirrors nsfs
behavior", but, unlike the corresponding procfs paths, it does so without
holding the target task's exec_update_lock.
proc_ns_get_link() and proc_ns_readlink() both take exec_update_lock for
reading around the ptrace check and the namespace lookup, so that the
credentials used for the access decision match those of the task when its
namespace is read. Without it, a caller can pass the check against the
target's old credentials and then read the namespace after the target has
execve()'d a setuid binary and committed new credentials -- accessing
namespace information it should have been denied.
Hold exec_update_lock for reading around the ptrace check and the
namespace lookup so that pidfd truly mirrors nsfs behavior, as the comment
already claims. open_namespace() itself runs outside the lock: once a
namespace reference is obtained it carries its own refcount and is opened
with the caller's own credentials, so a concurrent execve() on the target
can no longer affect the outcome.
Published Sep 11, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
timers/itimer: Zero-init old itimerval before copy to userspace
On native sparc64, struct __kernel_old_timeval contains a four-byte hole
after tv_usec because tv_sec is 64-bit while __kernel_suseconds_t is 32-bit.
put_itimerval() fills only the named fields in a stack-allocated
__kernel_old_itimerval and copies the entire object to userspace, so
getitimer() can expose the two padding holes.
Zero-initialize the aggregate before assigning the fields so implicit
padding is deterministic before it crosses the user/kernel boundary.
Published Sep 11, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
rust: devres: fix race between concurrent revokers
There is a potential race condition when two paths try to revoke a
Devres concurrently.
The driver core's devres_release_all() calls Revocable::revoke() via the
release callback, while Devres::drop() calls revoke_nosync() on another
CPU.
The revoker that does not claim the is_available swap returns
immediately, but the revoker that did may still be executing
drop_in_place() on the inner data. This can cause a use-after-free when
the other revoker's caller proceeds to drop adjacent resources that
drop_in_place() still references (e.g., Devres<DmaMappedSgt> racing with
SGTable freeing the backing sg_table and pages).
Fix this by adding a Completion. The release callback signals the
Completion after revoke() finishes, and Devres::drop() waits for it when
it loses the is_available swap. This ensures the wrapped object is fully
torn down before Devres::drop() returns.
Published Sep 11, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
KEYS: trusted: Fix TPM teardown ordering
trusted_tpm_exit() drops the TPM chip reference and frees the digest
array before unregistering the trusted key type. key_type_lookup()
holds key_types_sem for reading until the key operation finishes, while
unregister_key_type() takes it for writing. It therefore provides the
synchronization point that must precede backend teardown.
The current order permits this interleaving:
CPU 0 CPU 1
trusted_tpm_exit() key_type_lookup("trusted")
put_device(&chip->dev) trusted_tpm_seal()
kfree(digests) pcrlock()
unregister_key_type() tpm_pcr_extend(..., digests)
CPU 1 can consequently dereference the freed digest array. The chip can
also be released before callbacks stop using it.
KASAN reported:
BUG: KASAN: slab-use-after-free in tpm_pcr_extend+0x1f0/0x200
Read of size 2 at addr ffff88810872d000 by task poc/89
Call Trace:
tpm_pcr_extend+0x1f0/0x200
pcrlock+0x42/0x70 [trusted]
trusted_tpm_seal+0x1b6/0x570 [trusted]
trusted_instantiate+0x293/0x340 [trusted]
__key_instantiate_and_link+0xb2/0x2b0
__key_create_or_update+0x61e/0xb50
__do_sys_add_key+0x1b8/0x310
Allocated by task 88:
__kmalloc_noprof+0x1a7/0x490
do_one_initcall+0xa1/0x390
do_init_module+0x2df/0x840
Freed by task 90:
kfree+0x131/0x3c0
trusted_tpm_exit+0x59/0xa0 [trusted]
__do_sys_delete_module+0x346/0x510
Move unregister_key_type() before releasing either resource. This stops
new lookups and waits for in-flight key operations to finish before the
backend state is destroyed.
Published Sep 11, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
apparmor: fix cred UAF caused by begin_current_label_crit_section()
AppArmor's begin_current_label_crit_section() is a scary function called
from lots of LSM hooks (in particular VFS/socket-related ones) that checks
if the label referenced by the current creds is marked FLAG_STALE, and if
so, attempts to use aa_replace_current_label() to replace the creds with an
updated version that uses a new label.
The first problem with this is that it would directly lead to UAF of
`struct cred` if anything in the kernel takes a pointer to the current
creds and accesses these past a security hook invocation that replaces
creds, like so:
```
const struct cred *cred = current_cred();
alloc_file_pseudo(...);
uid_t uid = cred->euid;
```
I don't know if anything in the kernel actually does this, but I think it
is very surprising that this pattern could lead to UAF.
The second problem is that things go wrong when aa_replace_current_label()
runs with overridden credentials. aa_replace_current_label() bails out if
`current_cred() != current_real_cred()` (mirroring the check in
proc_pid_attr_write()), but this check can't actually reliably detect
overridden credentials because the overridden creds can be the same as the
objective creds.
So in approximately the following scenario, things go wrong:
1. task begins with <creds A> (as both objective and subjective creds),
with refcount=2
2. task grabs an extra reference on <creds A> for overriding
3. task calls override_creds(<creds A>), which returns a pointer to the old
subjective creds (<creds A>)
4. task enters AppArmor LSM hook
5. AppArmor checks that objective/subjective creds are equal
6. AppArmor replaces both cred pointers with <creds B> and drops 2 refs on
<creds A>
7. task leaves AppArmor LSM hook
8. task calls revert_creds(<creds A>)
9. now task->cred is <creds A> while task->real_cred is <creds B>, but the
task_struct logically holds two references to <creds B>
10. another task drops the extra reference on <creds A> that was used for
overriding, refcount drops to 0
11. now task->real_cred points to freed creds
At this point, any access to current_cred() will be UAF.
I have a test case where I run aa-disable on a profile while a process
using that profile is blocked on splice() from a FUSE passthrough file into
a full pipe; after the profile update, the pipe becomes empty, splice()
resumes, the credentials go out of sync, and a subsequent getuid() syscall
results in a KASAN UAF splat.
To fix this, instead of directly replacing creds, do it via task_work that
will run at the end of the current syscall. (The point in time at which the
cred replacement happens should have no correctness impact; it is just a
performance optimization to avoid unnecessarily touching the refcount of
the new label.)
Note that AppArmor still performs direct cred replacements in the
sb_pivotroot LSM hook after this change, and that direct cred replacements
can still happen in VFS ->write() callbacks via proc_pid_attr_write().
There are two options for what to do with aa_dup_task_ctx(): Either
explicitly reset new->label_replacement_pending after the entire
aa_task_ctx has been copied, or switch to manually copying members over.
I am switching to manually copying members over because that should make
bugs more obvious.
Published Sep 11, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
apparmor: fix out-of-bounds write when null terminating a label vec
aa_vec_unique() null terminates at vec[n - dups] when VEC_FLAG_TERMINATE
is passed. If the components are all distinct no duplicates are dropped,
dups is 0 and the terminator goes to vec[n], so the caller has to provide
room for n + 1 entries.
aa_label_strn_parse() sets up its vector with vec_setup(profile, vec, len,
gfp) and then calls aa_vec_unique(vec, len, VEC_FLAG_TERMINATE), but
vec_setup() does not reserve the terminator entry. Up to LOCAL_VEC_ENTRIES
it uses the local array of LOCAL_VEC_ENTRIES pointers, above that it
allocates exactly len pointers. The terminator therefore lands one entry
past the end of the local array when len is LOCAL_VEC_ENTRIES, and one
entry past the end of the allocation when len is larger.
len comes from the number of "//&" separated components in the label name
and label_count_strn_entries() does not bound it. An unprivileged task
reaches the parse by writing to /proc/self/attr/apparmor/current or through
lsm_set_self_attr(2), both of which go through do_setattr(), and the name
is parsed before the change_profile permission is checked.
The query_label() path behind the securityfs .access file, which is
mode 0666, performs no permission check at all. Every component has to
resolve to a loaded profile, so a system with policy loaded is required.
The other two VEC_FLAG_TERMINATE users work on a label vec that
aa_label_alloc() has already sized with "+ 1 for null terminator entry on
vec". Reserve the same entry in vec_setup() and DEFINE_VEC(). Passing
len + 1 from the caller instead would move len == LOCAL_VEC_ENTRIES out of
the local array and into kzalloc().
Published Sep 11, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
mm, swap: don't free a hibernation slot that is in the swap cache
A slot with a folio in the swap cache is freed when the folio leaves the
cache, not when its count drops. swap_put_entries_cluster() follows that
rule. swap_free_hibernation_slot() does not, it calls
__swap_cluster_free_entries() whether or not a folio sits on the slot.
Cluster readahead can put one there. It walks a raw page_cluster sized
window of offsets around the faulting entry, and a hibernation slot passes
__swap_cache_add_check() because it is not a folio and its count is not
zero. Freeing the slot then clears the entry under that folio.
The folio is now unreachable from the swap table, and the offset goes back
to the allocator. The folio is still on the LRU though, so reclaim can
pick it up later. It then takes the old offset out of folio->swap and
overwrites the table entry there, which by then may belong to someone
else.
This bug can trigger silent memory corruption, process crashes, or data
instability across completely unrelated userspace applications - typically
occurring when uswsusp is preparing the hibernation image.
I found this while working on giving hibernation slots their own marker in
the swap table, which I had discussed with Kairui.
(https://lore.kernel.org/linux-mm/abp7aDgYLrxF3Me8@KASONG-MC4/) As far as
I know there are no reports, so there is no Reported-by/Closes to add.
Check for a cached folio before freeing. The slot is then left in the
ordinary state where only the swap cache holds it, and it is freed when
the folio leaves the cache, either through the reclaim below or through
normal reclaim later.
Published Sep 11, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
mm/kmemleak: avoid soft lockup when scanning task stacks
Patch series "mm/kmemleak: avoid soft lockup when scanning task", v3.
kmemleak_scan() scans every task stack under one rcu_read_lock() with no
reschedule point, which can trip the soft lockup watchdog on hosts with
very many threads.
That prints the following message, depending on the workload+host
configuration:
watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537]
scan_block
kmemleak_scan
kmemleak_scan_thread
kthread
Patch 1 walks the tasks with find_ge_pid() so the scan reschedules between
tasks
Patches 2-3 let the scan loops stop early once a scan is interrupted.
This patch (of 3):
kmemleak_scan() walks every thread and scans its kernel stack under a
single rcu_read_lock() with no reschedule point. On a host with very many
threads -- amplified by KASAN/lockdep in debug builds -- this loop can hog
a CPU long enough to trip the soft lockup watchdog:
watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [kmemleak:537]
scan_block
kmemleak_scan
kmemleak_scan_thread
kthread
A cond_resched() cannot be added directly: the loop runs inside an RCU
read-side critical section.
Walk the tasks one PID at a time with find_ge_pid(), taking the RCU read
lock only to look up and pin each task. The stack is then scanned with no
lock held, so cond_resched() runs between tasks and the scan stops early
on scan_should_stop(). This follows the next_tgid()/task_seq_get_next()
iteration pattern and keeps each RCU critical section short.
Published Sep 11, 2026 · Updated Oct 19, 2026
High · CVSS 7.8
In the Linux kernel, the following vulnerability has been resolved:
mm/mempolicy: skip non-present PMDs when queueing folios
Patch series "mm: handle device-private PMDs in walk callbacks", v3.
Since commit 368076f52ebe ("mm/huge_memory: add device-private THP support
to PMD operations") a PMD may hold a device-private swap entry whenever an
HMM-based GPU driver migrates an anonymous THP folio to device memory via
migrate_vma_pages().
pmd_trans_huge_lock() succeeds for such PMDs (pmd_is_huge() returns true
for any non-present, non-none huge PMD), so several MM walk callbacks that
used to assume present THP or migration entry are now reachable with a
device-private PMD. The results range from a VM_BUG_ON() firing on debug
kernels, to an oops on a bogus vmemmap dereference, to silently isolating
an unrelated live folio from LRU in the aliasing case.
This patch (of 3):
queue_folios_pmd() is called under pmd_trans_huge_lock(), whose
pmd_is_huge() check returns true for any non-present, non-none PMD
softleaf. Passing such a PMD to pmd_folio() treats the softleaf encoding
as a hardware PFN and can return a bogus folio pointer.
Mirror queue_folios_pte_range(): handle non-present entries before looking
up a folio. Keep migration entries counted as failures, but skip other
non-present PMDs such as device-private entries.
Potential trigger: an HMM-based GPU driver migrates an anonymous THP folio
to device memory via migrate_vma_pages(), leaving a device-private PMD.
Userspace then calls mbind(), migrate_pages() or set_mempolicy_home_node()
on that range.
Published Sep 11, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
mm/mglru: fix and remove redundant unevictable folio handling
sort_folio() has a shortcut for moving folios that are no longer evictable
but are still sitting on a generation list. However, this shortcut is
buggy. It does not follow the PG_lru usage convention, and it has a more
serious issue.
Unevictable folios are not threaded on lists[LRU_UNEVICTABLE], so that
folio->lru can be reused to hold folio->mlock_count (see the comment in
lruvec_init()). Hence lruvec_add_folio() skips the list_add() for them,
and every other place that turns a folio unevictable initialises
mlock_count explicitly: lru_add() sets it to 0, __mlock_folio() and
__mlock_new_folio() set it to !!folio_test_mlocked(folio). sort_folio()
sets nothing, and the lru_gen_del_folio() right above it may have already
poisoned folio->lru via list_del(), so mlock_count ends up aliasing
LIST_POISON2, which reads as 0x122, i.e. 290. The result is user
visible. On munlock, __munlock_folio() decrements that bogus count, finds
it still non-zero and bails out before clearing PG_mlocked, so the folio
remains unevictable and the Mlocked accounting stays inflated until the
folio is freed.
The shortcut also touches the LRU flags in the wrong order. It calls
lru_gen_del_folio() while PG_lru is still set, so a concurrent
folio_test_clear_lru() (e.g. compaction, folio_isolate_lru()) can succeed
on a folio that has already been taken off the generation list, which may
lead to unexpected behavior.
So fix it by isolating them as common folios and letting the generic
shrink path cull them. This matches the classical LRU behavior, and there
should be no visible effect on the generic eviction or isolation behavior.
There is no performance concern either, such a folio goes through this
once, and then it is off the generation lists for good.
Published Sep 11, 2026 · Updated Oct 19, 2026
Unknown · CVSS Not scored
In the Linux kernel, the following vulnerability has been resolved:
mm/migrate: report RCU-tasks quiescent states in migrate_pages_batch()
migrate_pages_batch() unmaps each folio before moving it, and every
unmap runs the mmu_notifier invalidate callbacks. On KVM hosts
try_to_migrate() ends up in kvm_mmu_notifier_invalidate_range_start() ->
tdp_mmu_zap_leafs(), which is expensive, so unmapping a large batch keeps
the CPU busy for a long time.
The loop already calls cond_resched(), but on PREEMPTION kernels that is
a no-op, and involuntary preemption is not a Tasks-RCU quiescent state.
A long batch therefore never reports a quiescent state, and the
migrating task (e.g. kcompactd) becomes a Tasks-RCU holdout, stalling the
Tasks-RCU grace period for minutes, which is common at Meta fleet:
INFO: rcu_tasks detected stalls on tasks:
0000000055349ecc: .. nvcsw: 1157401/1157401 holdout: 1 idle_cpu: -1/56 task:kcompactd0 state:R running task
Call Trace:
tdp_mmu_zap_leafs
tdp_mmu_next_root
gfn_to_pfn_cache_invalidate_start
kvm_mmu_notifier_invalidate_range_start
__mmu_notifier_invalidate_range_start
try_to_migrate_one
try_to_migrate
migrate_pages_batch
migrate_pages
compact_zone
compact_node
kcompactd
kthread
Use cond_resched_tasks_rcu_qs() so a quiescent state is reported even
when cond_resched() does nothing.
This has also been discussed at [1]
Published Sep 11, 2026 · Updated Oct 19, 2026
