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

CVE-2026-99040: KEYS: Fix add_key() race with keyring restriction

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: 0.19% (FIRST EPSS).
  • Fixed version: Linux Linux 11516a0c402a6c1fa52254aa70d8d65fb921e59e, 24806fc9bca28fa1433bf938d1424dcb45d80e50, 305f1828b871dd46bf41addeb6f11d2c162dcb25; 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 11516a0c402a6c1fa52254aa70d8d65fb921e59e, 24806fc9bca28fa1433bf938d1424dcb45d80e50, 305f1828b871dd46bf41addeb6f11d2c162dcb25; 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: KEYS: Fix add_key() race with keyring restriction __key_create_or_update() snapshots keyring->restrict_link before taking the destination keyring's semaphore. keyring_restrict() installs a restriction while holding that semaphore. This allows a writer to observe no restriction, wait for the keyring owner to install a reject-all restriction and return successfully, and then link a key using the stale NULL snapshot. The writer only needs write permission on the destination keyring. Move the restrict_link read after __key_link_lock() and __key_link_begin(). The read and the subsequent restriction check are then serialized with restriction installation by keyring->sem. The race was reproduced on v7.2.8 in 19 executions where restriction installation returned before the link completed. All 19 linked the key despite the reject-all restriction. With this change, 312 executions reached the same ordering and every add_key() call failed with -EPERM. The issue was found by manual concurrency analysis assisted by AI-based analysis and independently verified with a QEMU reproducer and kernel instrumentation.

—No exploit Fix available
Published
Oct 23, 2026
Updated
Oct 30, 2026
EPSS
0.1% · 8th 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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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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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

    • 4.7affected
    • 5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c and later · before 24806fc9bca28fa1433bf938d1424dcb45d80e50affected · git
    • 5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c and later · before 9a5c2700336878465a630804a2d21864f22eca9caffected · git
    • 5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c and later · before b3e404550dc2b7f3d4bb64b1da8005a1fa9a798daffected · git
    • 5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c and later · before 305f1828b871dd46bf41addeb6f11d2c162dcb25affected · git
    • 5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c and later · before f99399b48e3edd6851fac34cd329bab9f1f33bafaffected · git
    • 5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c and later · before 11516a0c402a6c1fa52254aa70d8d65fb921e59eaffected · git
    • 5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c and later · before da0b595d8e6e2dd798f6e34e09dc51a13b888514affected · git
    • 5ac7eace2d00eab5ae0e9fdee63e38aee6001f7c and later · before dd3ea3fcba7c75493760cdbccd35f029597e8d5eaffected · git
    • before 4.7not 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 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.11-17.2.11-1

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-2026-99038Oct 23, 2026 · memstick: rtsx_usb_ms: complete requests after eject instead of dropping them
    0Monitor
  • ← EarlierCVE-2026-99039Oct 23, 2026 · memstick: core: wait for request completion before freeing card
    0Monitor
  • Later →CVE-2026-99041Oct 23, 2026 · ip6_gre: remove obsolete ERSPAN PMTU update
    0Monitor

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 Linux11516a0c402a6c1fa52254aa70d8d65fb921e59eVendor (CNA)
Linux Linux24806fc9bca28fa1433bf938d1424dcb45d80e50Vendor (CNA)
Linux Linux305f1828b871dd46bf41addeb6f11d2c162dcb25Vendor (CNA)
Linux Linux9a5c2700336878465a630804a2d21864f22eca9cVendor (CNA)
Linux Linuxb3e404550dc2b7f3d4bb64b1da8005a1fa9a798dVendor (CNA)
Linux Linuxda0b595d8e6e2dd798f6e34e09dc51a13b888514Vendor (CNA)
Linux Linuxdd3ea3fcba7c75493760cdbccd35f029597e8d5eVendor (CNA)
Linux Linuxf99399b48e3edd6851fac34cd329bab9f1f33bafVendor (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:linux6.12.113-1 · 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 8, 2026+16 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