VulnerabilityPublished 28 Oct 2026

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

Source GCVE Database

Authoritative record:CVE-2026-99179

Not known to be exploited · fixed in 811fb6d0b07605e8e8d93bde8748be4b3028809a : patch Linux kernel soon.

Data as of 28 Oct 2026, 13:46 UTC

Severity

High

Rated High by Threat Radar's AI analysis · 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.

ghsa-6fpx-qf4r-r7v5

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–

AI-suggested

A fix is available that corrects the memory ordering by publishing nr_notes last with smp_store_release() and reading it with smp_load_acquire() in post_one_notification(). Users should apply the official kernel patch that addresses this race condition to prevent exploitation.

Description

A race condition in the Linux kernel's watch_queue subsystem was fixed. The vulnerability involves a race between watch_queue_set_size() and post_one_notification() functions, which can lead to a NULL pointer dereference and kernel panic. An unprivileged user can trigger this by racing certain ioctl calls on a notification pipe, causing a fatal exception in the kernel.

Impact

An unprivileged user can reliably trigger a kernel NULL pointer dereference leading to a kernel panic, causing a denial of service. This can crash the system and disrupt normal operations.

Summary

The Linux kernel had a race condition in the watch_queue subsystem where watch_queue_set_size() published multiple related fields with plain stores, while post_one_notification() read them with plain loads under a different lock without proper memory ordering. This allowed post_one_notification() to read a non-zero nr_notes and then dereference a NULL notes pointer, causing a kernel NULL pointer dereference and panic. The issue was fixed by using smp_store_release() to publish nr_notes last and smp_load_acquire() to read it first, ensuring proper memory ordering and preventing the race.

References

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