VulnerabilityPublished 18 Feb 2026Updated 5 Nov 2026

CVE-2026-23223: Linux kernel · xfs: fix UAF in xchk_btree_check_block_owner

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in ed82e7949f5cac3058f4100f3cd670531d41a266 : update Linux kernel when convenient.

Data as of 5 Nov 2026, 23:24 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

EPSS

0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-05.

Patch

Available – fixed in ed82e7949f5cac3058f4100f3cd670531d41a266, ba5264610423d9653aa36920520902d83841bcfd, 1d411278dda293a507cb794db7d9ed3511c685c6 +1

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 5 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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 ed82e7949f5cac3058f4100f3cd670531d41a266, ba5264610423d9653aa36920520902d83841bcfd, 1d411278dda293a507cb794db7d9ed3511c685c6 or 1c253e11225bc5167217897885b85093e17c2217.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ ec793e690f801d97a7ae2a0d429fea1fee4d44aa, < ed82e7949f5cac3058f4100f3cd670531d41a266	Fixed in ed82e7949f5cac3058f4100f3cd670531d41a266
LinuxLinux	Affected ≥ ec793e690f801d97a7ae2a0d429fea1fee4d44aa, < ba5264610423d9653aa36920520902d83841bcfd	Fixed in ba5264610423d9653aa36920520902d83841bcfd
LinuxLinux	Affected ≥ ec793e690f801d97a7ae2a0d429fea1fee4d44aa, < 1d411278dda293a507cb794db7d9ed3511c685c6	Fixed in 1d411278dda293a507cb794db7d9ed3511c685c6
LinuxLinux	Affected ≥ ec793e690f801d97a7ae2a0d429fea1fee4d44aa, < 1c253e11225bc5167217897885b85093e17c2217	Fixed in 1c253e11225bc5167217897885b85093e17c2217
LinuxLinux	Affected =6.9	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: xfs: fix UAF in xchk_btree_check_block_owner We cannot dereference bs->cur when trying to determine if bs->cur aliases bs->sc->sa.{bno,rmap}_cur after the latter has been freed. Fix this by sampling before type before any freeing could happen. The correct temporal ordering was broken when we removed xfs_btnum_t.

References

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