CVE-2026-89482: nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
In the Linux kernel, the following vulnerability has been resolved:
nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
Commit 25e5cb780e62 ("nvme-tcp: fix possible crash in write_zeroes
processing") established that blk_rq_payload_bytes() must not be read
without first checking blk_rq_nr_phys_segments(), and recorded the
result in nvme_tcp_setup_cmd_pdu() as req->data_len. The receive side
was left as it was.
The two differ for REQ_OP_WRITE_ZEROES, which has no physical segments
but a non-zero blk_rq_bytes(), so setup leaves req->iter untouched
while the receive gate lets a C2HData through and nvme_tcp_recv_data()
copies into whatever the previous command on that tag left there. The
driver-private area is zeroed only when the tag set is allocated.
Reproduced with a test target that leaves a residual iterator on a tag
and then sends a C2HData for a WRITE_ZEROES command on the same tag:
BUG: KASAN: wild-memory-access in _copy_to_iter+0x642/0x1330
Write of size 512 at addr ffe728c2175dfa81 by task kworker/0:1H/103
CPU: 0 UID: 0 PID: 103 Comm: kworker/0:1H Not tainted 7.2.0-rc5-NVMETCP-gf5098b6bae76 #1 PREEMPT(lazy)
Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: nvme_tcp_wq nvme_tcp_io_work
Call Trace:
<TASK>
dump_stack_lvl+0x53/0x70
kasan_report+0xce/0x100
? _copy_to_iter+0x642/0x1330
kasan_check_range+0x105/0x1b0
__asan_memcpy+0x3c/0x60
_copy_to_iter+0x642/0x1330
? __pfx_sock_has_perm+0x10/0x10
? worker_thread+0x45b/0xd10
? __pfx__copy_to_iter+0x10/0x10
? _raw_spin_lock_bh+0x83/0xe0
? __pfx__raw_spin_lock_bh+0x10/0x10
__skb_datagram_iter+0xf3/0x820
? __pfx_simple_copy_to_iter+0x10/0x10
? __asan_memcpy+0x3c/0x60
? skb_copy_bits+0x58d/0x830
skb_copy_datagram_iter+0x37/0x120
nvme_tcp_recv_skb+0xa07/0x4320
? __pfx_nvme_tcp_recv_skb+0x10/0x10
__tcp_read_sock+0x1ab/0x810
? __pfx_nvme_tcp_recv_skb+0x10/0x10
? __pfx_lock_sock_nested+0x10/0x10
? __pfx___tcp_read_sock+0x10/0x10
nvme_tcp_try_recv+0x152/0x1e0
? __pfx_nvme_tcp_try_recv+0x10/0x10
? __pfx_mutex_unlock+0x10/0x10
nvme_tcp_io_work+0x1e4/0x6c0
? __schedule+0x181a/0x49f0
? __pfx_nvme_tcp_io_work+0x10/0x10
process_one_work+0x633/0x1030
Keep the blk_rq_payload_bytes() test and add req->data_len to it. The
old test is what rejects a C2HData naming a tag that is no longer in
flight, because blk_update_request() zeroes rq->__data_len on
completion; req->data_len and req->curr_bio are driver-private and
survive completion, so they cannot stand in for it. Setup initialises
the iterator only when both req->curr_bio and req->data_len are set, so
the gate now tests the same two.
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
cve · low confidence lookup
CVE-2026-89482 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
1CVSS vectors
3Timeline events
1ADP providers
9Source links
SSVC decision data
CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: total
CVSS vector scores
1 official score
We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.