VulnerabilityPublished 23 Oct 2026

CVE-2026-98961: Linux kernel · btrfs: unlock inode and extent in caller when io_uring read extent fails

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in b6e8add5d79d1f6f819a054c833bab452bd7365d : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:30 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in b6e8add5d79d1f6f819a054c833bab452bd7365d, ada1fc725a4db407294ae90a0d40ef1c46f457f2, 2797eb38773a96914ccedeec71eb2144645400b2

Exploitation evidence

Disclosed: evidence found.
CVE published 23 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.

What to do

Upgrade Linux kernel to b6e8add5d79d1f6f819a054c833bab452bd7365d, ada1fc725a4db407294ae90a0d40ef1c46f457f2 or 2797eb38773a96914ccedeec71eb2144645400b2.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 34310c442e175f286b4c06ab5caa4e0b267ea31c, < b6e8add5d79d1f6f819a054c833bab452bd7365d	Fixed in b6e8add5d79d1f6f819a054c833bab452bd7365d
LinuxLinux	Affected ≥ 34310c442e175f286b4c06ab5caa4e0b267ea31c, < ada1fc725a4db407294ae90a0d40ef1c46f457f2	Fixed in ada1fc725a4db407294ae90a0d40ef1c46f457f2
LinuxLinux	Affected ≥ 34310c442e175f286b4c06ab5caa4e0b267ea31c, < 2797eb38773a96914ccedeec71eb2144645400b2	Fixed in 2797eb38773a96914ccedeec71eb2144645400b2
LinuxLinux	Affected =6.13	Fixed in–

AI-suggested

A fix is available in the Linux kernel commits identified by hashes b6e8add5d79d1f6f819a054c833bab452bd7365d, ada1fc725a4db407294ae90a0d40ef1c46f457f2, and 2797eb38773a96914ccedeec71eb2144645400b2. Users should update to these fixed kernel versions or later to remediate this issue.

Description

A vulnerability in the Linux kernel's btrfs filesystem code was fixed where inode and extent locks were not properly released on failure during io_uring read extent operations. Specifically, a failure in pages-array allocation returned an error without unlocking, potentially causing resource locking issues.

Impact

Improper unlocking of inode and extent locks on failure could lead to resource locking issues within the btrfs filesystem, potentially causing system instability or deadlocks. No direct exploitation or active attacks are known.

Summary

The Linux kernel's btrfs_uring_read_extent() function acquires inode shared and extent locks before proceeding. Previously, on failure paths such as pages-array allocation failure returning -ENOMEM, the function did not release these locks, leading to potential lock retention issues. The fix moves the unlocking responsibility to the caller on all failure returns, aligning with the error handling path of copy_to_user(). The deferred -EIOCBQUEUED path continues to unlock in btrfs_uring_read_finished(). This correction ensures proper lock release on all failure scenarios.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 15:36 UTC

Technical details

References

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