VulnerabilityPublished 28 Oct 2026

CVE-2026-99179: Linux kernel · watch_queue: Fix note pool publication race in watch_queue_set_size()

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in 811fb6d0b07605e8e8d93bde8748be4b3028809a : update Linux kernel when convenient.

Data as of 28 Oct 2026, 10:58 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

Patch: Available – fixed in 811fb6d0b07605e8e8d93bde8748be4b3028809a, 9e73a6754457ffed8399b835552013b9363e51d1, 5e531d62f1f8834faf7a4eed0d41105cf6570a8f

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to 811fb6d0b07605e8e8d93bde8748be4b3028809a, 9e73a6754457ffed8399b835552013b9363e51d1 or 5e531d62f1f8834faf7a4eed0d41105cf6570a8f.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ c73be61cede5882f9605a852414db559c0ebedfd, < 811fb6d0b07605e8e8d93bde8748be4b3028809a	Fixed in 811fb6d0b07605e8e8d93bde8748be4b3028809a
LinuxLinux	Affected ≥ c73be61cede5882f9605a852414db559c0ebedfd, < 9e73a6754457ffed8399b835552013b9363e51d1	Fixed in 9e73a6754457ffed8399b835552013b9363e51d1
LinuxLinux	Affected ≥ c73be61cede5882f9605a852414db559c0ebedfd, < 5e531d62f1f8834faf7a4eed0d41105cf6570a8f	Fixed in 5e531d62f1f8834faf7a4eed0d41105cf6570a8f
LinuxLinux	Affected =5.8	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: watch_queue: Fix note pool publication race in watch_queue_set_size() There is a race between watch_queue_set_size() and post_one_notification(). watch_queue_set_size() publishes wqueue->notes, notes_bitmap, nr_pages and nr_notes with plain stores, and post_one_notification() reads them with plain loads under a different lock, so nothing orders the four stores against the poster's loads: depending on the build, notes can be stored last (gcc 14 on x86-64 does this). Since keyctl_watch_key() lets a watch attach to a queue before it is sized, post_one_notification() can already be running on another CPU at that moment: it reads nr_notes > 0, passes its bounds check, and then reads notes while it is still NULL, dereferencing notes[0]. An unprivileged user triggers this reliably by watching one of its own keys through a notification pipe and racing ioctl(IOC_WATCH_QUEUE_SET_SIZE) on that pipe against keyctl(KEYCTL_SETPERM) on the key from another CPU, triggering: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:post_one_notification.isra.0+0xa2/0x1e0 Call Trace: __post_watch_notification+0x148/0x180 keyctl_setperm_key+0x119/0x130 do_syscall_64+0x108/0x4c0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Kernel panic - not syncing: Fatal exception in interrupt Fix this by publishing nr_notes last with smp_store_release(), and by reading it once with smp_load_acquire() in post_one_notification() before the bitmap and the page array are touched. A poster that observes a non-zero nr_notes then also observes the pool behind it; one that observes zero drops the notification as before.

References

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