{"id":"CVE-2026-64435","title":"audit: Fix data races of skb_queue_len() readers on audit_queue","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\naudit: Fix data races of skb_queue_len() readers on audit_queue\n\nMultiple readers access audit_queue.qlen via skb_queue_len() without\nholding the queue lock or using RE…","severity":"high","cvss":8.2,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < 69f98fff30bdaa72b0cb0e7e078ab6456a0a59b0","Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < b35597bdae1a5d8395da4b9baa993b9b71f74d68","Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < e575dabb805252e3113fdc3f56f6ecacfde422d0","Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < 7ff42312ccde549f8c698723822c7db35107a39b","Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < a3d85dec60bb0622360fc176b2a51abdbe2ff0ad","Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < fe997a84a385f840b593ead92e575503a5046cee","Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < c5186201fa7030289cc4fe23fae87a3fcb566856","Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < c9a71daaecb2fb1d8c704545cc0b1c920b9bf5d7","Linux 4.10"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-16T15:40:38.595570Z"},"published":"2026-07-25","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:42:35.539Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-64435","references":[{"url":"https://git.kernel.org/stable/c/69f98fff30bdaa72b0cb0e7e078ab6456a0a59b0"},{"url":"https://git.kernel.org/stable/c/b35597bdae1a5d8395da4b9baa993b9b71f74d68"},{"url":"https://git.kernel.org/stable/c/e575dabb805252e3113fdc3f56f6ecacfde422d0"},{"url":"https://git.kernel.org/stable/c/7ff42312ccde549f8c698723822c7db35107a39b"},{"url":"https://git.kernel.org/stable/c/a3d85dec60bb0622360fc176b2a51abdbe2ff0ad"},{"url":"https://git.kernel.org/stable/c/fe997a84a385f840b593ead92e575503a5046cee"},{"url":"https://git.kernel.org/stable/c/c5186201fa7030289cc4fe23fae87a3fcb566856"},{"url":"https://git.kernel.org/stable/c/c9a71daaecb2fb1d8c704545cc0b1c920b9bf5d7"}],"tags":["cve.org"],"epss":0.00331,"epssPercentile":0.24769,"ingestedAt":"2026-10-16T17:24:46.819Z","slug":"CVE-2026-64435","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\naudit: Fix data races of skb_queue_len() readers on audit_queue\n\nMultiple readers access audit_queue.qlen via skb_queue_len() without\nholding the queue lock or using READ_ONCE(), while kauditd writes to\nthis field via the skb_dequeue() → __skb_unlink() path with WRITE_ONCE()\nprotected by a spinlock. This constitutes data races.\n\nAll affected skb_queue_len(&audit_queue) call sites:\n  - kauditd_thread() wait_event_freezable() condition\n  - audit_receive_msg() AUDIT_GET handler (s.backlog assignment)\n  - audit_receive() backlog check\n  - audit_log_start() backlog check and pr_warn()\n\nKCSAN reports the following conflicting access pattern (one example):\n==================================================================\nBUG: KCSAN: data-race in audit_log_start / skb_dequeue\n\nwrite (marked) to 0xffffffff8512ee20 of 4 bytes by task 661 on cpu 57:\n skb_dequeue+0x70/0xf0\n kauditd_send_queue+0x71/0x220\n kauditd_thread+0x1cb/0x430\n kthread+0x1c2/0x210\n ret_from_fork+0x162/0x1a0\n ret_from_fork_asm+0x1a/0x30\n\nread to 0xffffffff8512ee20 of 4 bytes by task 36586 on cpu 1:\n audit_log_start+0x2a0/0x6b0\n audit_core_dumps+0x64/0xa0\n do_coredump+0x14b/0x1260\n get_signal+0xeb2/0xf70\n arch_do_signal_or_restart+0x41/0x170\n exit_to_user_mode_loop+0xa2/0x1c0\n do_syscall_64+0x1a3/0x1c0\n entry_SYSCALL_64_after_hwframe+0x76/0xe0\n\nvalue changed: 0x00000001 -> 0x00000000\n==================================================================\n\nResolve the race by switching to lockless helper skb_queue_len_lockless(),\nwhich internally uses READ_ONCE() and properly pairs with the WRITE_ONCE()\nwrite accesses already present on the writer side.\n\n[PM: line length tweak]\n\n## Affected\n\n- `Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < 69f98fff30bdaa72b0cb0e7e078ab6456a0a59b0`\n- `Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < b35597bdae1a5d8395da4b9baa993b9b71f74d68`\n- `Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < e575dabb805252e3113fdc3f56f6ecacfde422d0`\n- `Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < 7ff42312ccde549f8c698723822c7db35107a39b`\n- `Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < a3d85dec60bb0622360fc176b2a51abdbe2ff0ad`\n- `Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < fe997a84a385f840b593ead92e575503a5046cee`\n- `Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < c5186201fa7030289cc4fe23fae87a3fcb566856`\n- `Linux >= 3197542482df22c2a131d4a813280bd7c54cedf5 < c9a71daaecb2fb1d8c704545cc0b1c920b9bf5d7`\n- `Linux 4.10`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":45.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}