CVE-2023-54226: af_unix: Fix data races around sk->sk_shutdown.
In the Linux kernel, the following vulnerability has been resolved:
af_unix: Fix data races around sk->sk_shutdown.
KCSAN found a data race around sk->sk_shutdown where unix_release_sock()
and unix_shutdown() update it under unix_state_lock(), OTOH unix_poll()
and unix_dgram_poll() read it locklessly.
We need to annotate the writes and reads with WRITE_ONCE() and READ_ONCE().
BUG: KCSAN: data-race in unix_poll / unix_release_sock
write to 0xffff88800d0f8aec of 1 bytes by task 264 on cpu 0:
unix_release_sock+0x75c/0x910 net/unix/af_unix.c:631
unix_release+0x59/0x80 net/unix/af_unix.c:1042
__sock_release+0x7d/0x170 net/socket.c:653
sock_close+0x19/0x30 net/socket.c:1397
__fput+0x179/0x5e0 fs/file_table.c:321
____fput+0x15/0x20 fs/file_table.c:349
task_work_run+0x116/0x1a0 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
exit_to_user_mode_prepare+0x174/0x180 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:297
do_syscall_64+0x4b/0x90 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x72/0xdc
read to 0xffff88800d0f8aec of 1 bytes by task 222 on cpu 1:
unix_poll+0xa3/0x2a0 net/unix/af_unix.c:3170
sock_poll+0xcf/0x2b0 net/socket.c:1385
vfs_poll include/linux/poll.h:88 [inline]
ep_item_poll.isra.0+0x78/0xc0 fs/eventpoll.c:855
ep_send_events fs/eventpoll.c:1694 [inline]
ep_poll fs/eventpoll.c:1823 [inline]
do_epoll_wait+0x6c4/0xea0 fs/eventpoll.c:2258
__do_sys_epoll_wait fs/eventpoll.c:2270 [inline]
__se_sys_epoll_wait fs/eventpoll.c:2265 [inline]
__x64_sys_epoll_wait+0xcc/0x190 fs/eventpoll.c:2265
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x72/0xdc
value changed: 0x00 -> 0x03
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 222 Comm: dbus-broker Not tainted 6.3.0-rc7-02330-gca6270c12e20 #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
Security readout for executives and security teams
Plain-English summary
This is a Linux kernel concurrency bug in Unix domain socket handling. A kernel race detector found unsynchronized reads and writes of a socket shutdown flag. The provided sources do not describe a proven security impact, CVSS score, or active exploitation.
Executive priority
Treat this as a kernel hygiene item with unclear business urgency. There is no active exploitation evidence in the supplied sources, but kernel race fixes should still be absorbed through standard patch management.
Technical view
The race is around sk->sk_shutdown in af_unix. unix_release_sock() and unix_shutdown() write it under unix_state_lock(), while unix_poll() and unix_dgram_poll() read it locklessly. The fix annotates accesses with WRITE_ONCE() and READ_ONCE().
Likely exposure
Exposure is limited to Linux systems running affected kernel versions listed in the CVE bundle. Unix domain sockets are common for local IPC, but the sources do not identify affected distributions, configurations, or reachable attack paths.
Exploitation context
The bundle marks KEV false and provides no cited evidence of exploitation. The issue was reported by Kernel Concurrency Sanitizer during testing on Linux 6.3.0-rc7 in QEMU, not from an observed attack.
Researcher notes
The record lacks CVSS, CWE, distro advisories, and impact detail. Analysis should focus on whether local Unix socket polling paths can trigger observable misbehavior on affected kernels and whether vendor backports match the stable commits.
Mitigation direction
Check vendor kernel advisories for CVE-2023-54226 coverage.
Update affected Linux kernels to vendor-fixed builds when available.
Confirm vendor backports include the referenced stable kernel commits.
Prioritize normal kernel patch cycles unless vendor guidance escalates severity.
Validation and detection
Inventory Linux kernel versions across servers, workstations, and appliances.
Compare versions against the affected versions in the CVE bundle.
Check distribution package changelogs for CVE-2023-54226 or af_unix sk_shutdown fixes.
Verify running kernels after reboot, not only installed packages.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Potential ATT&CK relevance
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CVE publishedCVE Program
The CVE record was published.
Dec 30, 2025, 12:11 UTC (UTC+00:00)
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