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CVE.org (no NVD analysis yet)· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.18% (FIRST EPSS).
  • Fixed version: Linux Linux 2137d487b25eefa862be70de489b64f4c679fe1f, 4b20867d80e7e91fb7db531f34035d91591ba405, 5e531d62f1f8834faf7a4eed0d41105cf6570a8f; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 6.6.161.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 2137d487b25eefa862be70de489b64f4c679fe1f, 4b20867d80e7e91fb7db531f34035d91591ba405, 5e531d62f1f8834faf7a4eed0d41105cf6570a8f; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 6.6.161.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Oct 28, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 7th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.8affected
    • c73be61cede5882f9605a852414db559c0ebedfd and later · before 2137d487b25eefa862be70de489b64f4c679fe1faffected · git
    • c73be61cede5882f9605a852414db559c0ebedfd and later · before 6aaa6c1a1b61aae332d6e7e0083140b86ea51e14affected · git
    • c73be61cede5882f9605a852414db559c0ebedfd and later · before 4b20867d80e7e91fb7db531f34035d91591ba405affected · git
    • c73be61cede5882f9605a852414db559c0ebedfd and later · before da52e5fcb2cae6acdc0d5722ff83499f8232b9d1affected · git
    • c73be61cede5882f9605a852414db559c0ebedfd and later · before f94c45f83e688e41dfe1b3a589806a0a25567260affected · git
    • c73be61cede5882f9605a852414db559c0ebedfd and later · before 811fb6d0b07605e8e8d93bde8748be4b3028809aaffected · git
    • c73be61cede5882f9605a852414db559c0ebedfd and later · before 9e73a6754457ffed8399b835552013b9363e51d1affected · git
    • c73be61cede5882f9605a852414db559c0ebedfd and later · before 5e531d62f1f8834faf7a4eed0d41105cf6570a8faffected · git
    • before 5.8not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.115-26.12.115-2
Debian:14linuxbefore 7.2.13-17.2.13-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-99177Oct 28, 2026 · KVM: SEV: Fix page dirtying in sev_gmem_post_populate()
    31Monitor
  • ← EarlierCVE-2026-99178Oct 28, 2026 · x86/kvm: Don't consume async #PF flags on a kernel #PF in NMI context
    0Monitor
  • Later →CVE-2026-99180Oct 28, 2026 · unicode: free the map after a grace period
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux2137d487b25eefa862be70de489b64f4c679fe1fVendor (CNA)
Linux Linux4b20867d80e7e91fb7db531f34035d91591ba405Vendor (CNA)
Linux Linux5e531d62f1f8834faf7a4eed0d41105cf6570a8fVendor (CNA)
Linux Linux6aaa6c1a1b61aae332d6e7e0083140b86ea51e14Vendor (CNA)
Linux Linux811fb6d0b07605e8e8d93bde8748be4b3028809aVendor (CNA)
Linux Linux9e73a6754457ffed8399b835552013b9363e51d1Vendor (CNA)
Linux Linuxda52e5fcb2cae6acdc0d5722ff83499f8232b9d1Vendor (CNA)
Linux Linuxf94c45f83e688e41dfe1b3a589806a0a25567260Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.159.1-1 on Azure Linux 3.06.6.161.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.12.115-2 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 9, 2026+12 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Exploit maturity— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records