VulnerabilityPublished 26 Oct 2026Updated 27 Oct 2026

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

Affects Linux kernelSource GCVE Database

Authoritative record:CVE-2026-98961· Medium

Not known to be exploited.

Data as of 28 Oct 2026, 02:13 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

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

Affected software

Product	Affected	Fixed in
Ubuntu 26.10linux`pkg:deb/ubuntu/linux?arch=source&distro=stonking`Other threats	Affected 7.0.0-14.14 – 7.3.0-9.9 6 affected builds	Fixed in–
Ubuntu 26.10linux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=stonking`Other threats	Affected 7.0.0-1004.4 – 7.3.0-1003.3 5 affected builds	Fixed in–
Ubuntu 26.10linux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=stonking`Other threats	Affected 7.0.0-1004.4 – 7.3.0-1003.3 5 affected builds	Fixed in–
Ubuntu 26.10linux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonking`Other threats	Affected =7.0.0-1004.4 =7.3.0-1002.3 =7.3.0-1003.4	Fixed in–
Ubuntu 26.10linux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=stonking`Other threats	Affected 7.0.0-1003.3 – 7.3.0-1003.3 5 affected builds	Fixed in–
Ubuntu 26.10linux-oracle`pkg:deb/ubuntu/linux-oracle?arch=source&distro=stonking`Other threats	Affected 7.0.0-1003.3 – 7.3.0-1003.3 5 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel. Users should update to patched kernel versions that include this correction. The affected versions include specific Linux kernel builds listed in the affectedVersions field. No additional mitigation actions are required beyond applying the official kernel updates.

Description

A vulnerability in the Linux kernel's btrfs filesystem code related to improper unlocking of inode and extent locks during io_uring read extent failures has been resolved. The issue involved inconsistent unlocking behavior on failure paths, potentially leading to resource locking issues. The fix ensures that inode and extent locks are properly released on all failure returns in the btrfs_uring_read_extent() function.

Impact

The vulnerability could cause inode and extent locks to remain held after certain failure conditions during btrfs io_uring read operations, potentially leading to resource contention or deadlocks within the kernel filesystem code. This may affect system stability or performance but does not indicate direct data corruption or privilege escalation. No known exploits in the wild have been reported.

Summary

CVE-2026-98961 addresses a flaw in the Linux kernel's btrfs filesystem where inode and extent locks were not consistently released when the io_uring read extent operation failed. Specifically, btrfs_uring_read_extent() acquires shared inode and extent locks before performing operations. On failure, the previous code unlocked these locks in an error path but failed to do so in the case of a pages-array allocation failure, returning -ENOMEM without unlocking. The fix moves unlocking responsibility to the caller on all failure returns, aligning with the behavior of the copy_to_user() error path. The deferred -EIOCBQUEUED path continues to unlock in btrfs_uring_read_finished(). This correction prevents potential lock leaks that could affect kernel stability or filesystem operations.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Oct 2026, 02:13 UTC

Technical details

References

Community reviews

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