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NVD / CVE Program· CNA Linux

CVE-2026-99226: keys: Avoid the owner account dereference in named keyring lookup

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 0b865fa477d94ac96c26848aab1fd176397de3f6, 40b12b93ae4ab9e22c3d571e9b09fd08afad53f6, 51409aaa01f8602552c336009fd22b226b0cdf1d.

Low priority for now. Upgrade to Linux Linux 0b865fa477d94ac96c26848aab1fd176397de3f6, 40b12b93ae4ab9e22c3d571e9b09fd08afad53f6, 51409aaa01f8602552c336009fd22b226b0cdf1d 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: Avoid the owner account dereference in named keyring lookup Named keyring lookup must keep the storage containing the owner UID alive through the namespace mapping check. find_keyring_by_name() reads keyring->user->uid under keyring_name_lock, but that lock protects the keyring's name entry and allocation, not its separate key_user. A named session-keyring join can overlap a privileged KEYCTL_CHOWN on another CPU. If the keyring holds the last reference to its old dynamic key_user and the ownership transfer succeeds, the following ordering is possible: Named join Chown find_keyring_by_name() keyctl_chown_key() read_lock(keyring_name_lock) down_write(key->sem) load old keyring->user replace key->user and key->uid up_write(key->sem) key_put(key) key_user_put(old user): free read old user->uid read_unlock(keyring_name_lock) Chown neither takes keyring_name_lock nor key_session_mutex, so it can free the old account between the pointer load and the UID read. The lookup then reads freed memory even though the keyring itself is alive. Use keyring->uid for the mapping check. key_alloc() initializes this inline owner UID and keyctl_chown_key() updates it on chown. The existing name lock keeps its containing keyring allocated throughout the check, so lookup no longer depends on the account's lifetime. This also matches the owner UID used by the permission check. KASAN report as below: BUG: KASAN: slab-use-after-free in find_keyring_by_name+0x577/0x5d0 Read of size 4 at addr ffff8881128ae2ec by task keycase/500

—No exploit Fix available
Published
Nov 2, 2026
Updated
Nov 3, 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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  • Not in KEV: no record of exploitation in the wild
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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

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—

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

    • 2.6.30affected
    • 2ea190d0a006ce5218baa6e798512652446a605a and later · before 77249d4b1bb5ad43552b7023c4a0978937aa7a56affected · git
    • 2ea190d0a006ce5218baa6e798512652446a605a and later · before 0b865fa477d94ac96c26848aab1fd176397de3f6affected · git
    • 2ea190d0a006ce5218baa6e798512652446a605a and later · before 6763329f673d261641c79212abf773af77b2c922affected · git
    • 2ea190d0a006ce5218baa6e798512652446a605a and later · before aa03c8fb4334f14d218020f7431debf2b7766865affected · git
    • 2ea190d0a006ce5218baa6e798512652446a605a and later · before c9664f780f861dd9f11f120c7a03ed0993671ebbaffected · git
    • 2ea190d0a006ce5218baa6e798512652446a605a and later · before b0830a26e2c3008a6e21863126b4a0e68b2761cdaffected · git
    • 2ea190d0a006ce5218baa6e798512652446a605a and later · before 5c6a9512887a6cc694d594d9c0b57c0841d215b5affected · git
    • 2ea190d0a006ce5218baa6e798512652446a605a and later · before 40b12b93ae4ab9e22c3d571e9b09fd08afad53f6affected · git
    • 2ea190d0a006ce5218baa6e798512652446a605a and later · before 51409aaa01f8602552c336009fd22b226b0cdf1daffected · git

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.115-16.12.115-1

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-2026-99224Nov 2, 2026 · keys: Protect the type name while describing a key
    28Monitor
  • ← EarlierCVE-2026-99225Nov 2, 2026 · keys: Check the authorization payload in process keyring searches
    0Monitor
  • Later →CVE-2026-99227Nov 2, 2026 · io_uring/waitid: prevent cancel reference wrap
    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 Linux0b865fa477d94ac96c26848aab1fd176397de3f6Vendor (CNA)
Linux Linux40b12b93ae4ab9e22c3d571e9b09fd08afad53f6Vendor (CNA)
Linux Linux51409aaa01f8602552c336009fd22b226b0cdf1dVendor (CNA)
Linux Linux5c6a9512887a6cc694d594d9c0b57c0841d215b5Vendor (CNA)
Linux Linux6763329f673d261641c79212abf773af77b2c922Vendor (CNA)
Linux Linux77249d4b1bb5ad43552b7023c4a0978937aa7a56Vendor (CNA)
Linux Linuxaa03c8fb4334f14d218020f7431debf2b7766865Vendor (CNA)
Linux Linuxb0830a26e2c3008a6e21863126b4a0e68b2761cdVendor (CNA)
Linux Linuxc9664f780f861dd9f11f120c7a03ed0993671ebbVendor (CNA)
debian:linux6.12.115-1 · 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 6, 2026+4 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).

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

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

References

Show all references (8 more)

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

All records