FKIE_CVE-2026-64435
Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-07-27 05:16
Severity
Summary
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]
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/audit.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "69f98fff30bdaa72b0cb0e7e078ab6456a0a59b0",
"status": "affected",
"version": "3197542482df22c2a131d4a813280bd7c54cedf5",
"versionType": "git"
},
{
"lessThan": "b35597bdae1a5d8395da4b9baa993b9b71f74d68",
"status": "affected",
"version": "3197542482df22c2a131d4a813280bd7c54cedf5",
"versionType": "git"
},
{
"lessThan": "e575dabb805252e3113fdc3f56f6ecacfde422d0",
"status": "affected",
"version": "3197542482df22c2a131d4a813280bd7c54cedf5",
"versionType": "git"
},
{
"lessThan": "7ff42312ccde549f8c698723822c7db35107a39b",
"status": "affected",
"version": "3197542482df22c2a131d4a813280bd7c54cedf5",
"versionType": "git"
},
{
"lessThan": "a3d85dec60bb0622360fc176b2a51abdbe2ff0ad",
"status": "affected",
"version": "3197542482df22c2a131d4a813280bd7c54cedf5",
"versionType": "git"
},
{
"lessThan": "fe997a84a385f840b593ead92e575503a5046cee",
"status": "affected",
"version": "3197542482df22c2a131d4a813280bd7c54cedf5",
"versionType": "git"
},
{
"lessThan": "c5186201fa7030289cc4fe23fae87a3fcb566856",
"status": "affected",
"version": "3197542482df22c2a131d4a813280bd7c54cedf5",
"versionType": "git"
},
{
"lessThan": "c9a71daaecb2fb1d8c704545cc0b1c920b9bf5d7",
"status": "affected",
"version": "3197542482df22c2a131d4a813280bd7c54cedf5",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"kernel/audit.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.10"
},
{
"lessThan": "4.10",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.96",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2-rc3",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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 READ_ONCE(), while kauditd writes to\nthis field via the skb_dequeue() \u2192 __skb_unlink() path with WRITE_ONCE()\nprotected by a spinlock. This constitutes data races.\n\nAll affected skb_queue_len(\u0026audit_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 -\u003e 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]"
}
],
"id": "CVE-2026-64435",
"lastModified": "2026-07-27T05:16:49.843",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.2,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 4.2,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-07-25T10:17:27.873",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/69f98fff30bdaa72b0cb0e7e078ab6456a0a59b0"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/7ff42312ccde549f8c698723822c7db35107a39b"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/a3d85dec60bb0622360fc176b2a51abdbe2ff0ad"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b35597bdae1a5d8395da4b9baa993b9b71f74d68"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c5186201fa7030289cc4fe23fae87a3fcb566856"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c9a71daaecb2fb1d8c704545cc0b1c920b9bf5d7"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/e575dabb805252e3113fdc3f56f6ecacfde422d0"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/fe997a84a385f840b593ead92e575503a5046cee"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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