Riskcovery

CVE-2026-64435

audit: Fix data races of skb_queue_len() readers on audit_queue

State
Published
Severity
8.2 High
Published
Jul 25, 2026
Updated
Oct 19, 2026
Reserved
Jul 19, 2026

Read the record on cve.org

Description

In the Linux kernel, the following vulnerability has been resolved:

audit: Fix data races of skb_queue_len() readers on audit_queue

Multiple readers access audit_queue.qlen via skb_queue_len() without holding the queue lock or using READ_ONCE(), while kauditd writes to this field via the skb_dequeue() → __skb_unlink() path with WRITE_ONCE() protected by a spinlock. This constitutes data races.

All affected skb_queue_len(&audit_queue) call sites: - kauditd_thread() wait_event_freezable() condition - audit_receive_msg() AUDIT_GET handler (s.backlog assignment) - audit_receive() backlog check - audit_log_start() backlog check and pr_warn()

KCSAN reports the following conflicting access pattern (one example): ================================================================== BUG: KCSAN: data-race in audit_log_start / skb_dequeue

write (marked) to 0xffffffff8512ee20 of 4 bytes by task 661 on cpu 57: skb_dequeue+0x70/0xf0 kauditd_send_queue+0x71/0x220 kauditd_thread+0x1cb/0x430 kthread+0x1c2/0x210 ret_from_fork+0x162/0x1a0 ret_from_fork_asm+0x1a/0x30

read to 0xffffffff8512ee20 of 4 bytes by task 36586 on cpu 1: audit_log_start+0x2a0/0x6b0 audit_core_dumps+0x64/0xa0 do_coredump+0x14b/0x1260 get_signal+0xeb2/0xf70 arch_do_signal_or_restart+0x41/0x170 exit_to_user_mode_loop+0xa2/0x1c0 do_syscall_64+0x1a3/0x1c0 entry_SYSCALL_64_after_hwframe+0x76/0xe0

value changed: 0x00000001 -> 0x00000000 ==================================================================

Resolve the race by switching to lockless helper skb_queue_len_lockless(), which internally uses READ_ONCE() and properly pairs with the WRITE_ONCE() write accesses already present on the writer side.

[PM: line length tweak]

Scores

CVSSScoreVectorSource
3.18.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:HLinux

Weaknesses

  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Affected Products

ProductVersions
LinuxLinux
  • 3197542482df22c2a131d4a813280bd7c54cedf5 to before 69f98fff30bdaa72b0cb0e7e078ab6456a0a59b0Affected
  • 3197542482df22c2a131d4a813280bd7c54cedf5 to before b35597bdae1a5d8395da4b9baa993b9b71f74d68Affected
  • 3197542482df22c2a131d4a813280bd7c54cedf5 to before e575dabb805252e3113fdc3f56f6ecacfde422d0Affected
  • 3197542482df22c2a131d4a813280bd7c54cedf5 to before 7ff42312ccde549f8c698723822c7db35107a39bAffected
  • 3197542482df22c2a131d4a813280bd7c54cedf5 to before a3d85dec60bb0622360fc176b2a51abdbe2ff0adAffected
  • 3197542482df22c2a131d4a813280bd7c54cedf5 to before fe997a84a385f840b593ead92e575503a5046ceeAffected
  • 3197542482df22c2a131d4a813280bd7c54cedf5 to before c5186201fa7030289cc4fe23fae87a3fcb566856Affected
  • 3197542482df22c2a131d4a813280bd7c54cedf5 to before c9a71daaecb2fb1d8c704545cc0b1c920b9bf5d7Affected
LinuxLinux
  • 4.10Affected
  • before 4.10Not affected
  • 5.10.261 through 5.10.*Not affected
  • 5.15.212 through 5.15.*Not affected
  • 6.1.178 through 6.1.*Not affected
  • 6.6.145 through 6.6.*Not affected
  • 6.12.96 through 6.12.*Not affected
  • 6.18.39 through 6.18.*Not affected
  • 7.1.4 through 7.1.*Not affected
  • 7.2 and laterNot affected

References

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