VulnerabilityPublished 28 Oct 2026

CVE-2026-99131: Linux kernel · xfs: fix capability check in xfs

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in e2f62a9744ebad3bcb6347a648e615026e9efeff : update Linux kernel when convenient.

Data as of 28 Oct 2026, 10:58 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

Patch: Available – fixed in e2f62a9744ebad3bcb6347a648e615026e9efeff, 7809ac0161c7c5f52ed348fb1ec683b2b454a83e, 19a1a22029ad3ae3604c763af6bd1195cb73648f

Exploitation evidence

Disclosed: evidence found.
CVE published 28 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 e2f62a9744ebad3bcb6347a648e615026e9efeff, 7809ac0161c7c5f52ed348fb1ec683b2b454a83e or 19a1a22029ad3ae3604c763af6bd1195cb73648f.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ eba0549bc7d100691c13384b774346b8aa9cf9a9, < e2f62a9744ebad3bcb6347a648e615026e9efeff	Fixed in e2f62a9744ebad3bcb6347a648e615026e9efeff
LinuxLinux	Affected ≥ eba0549bc7d100691c13384b774346b8aa9cf9a9, < 7809ac0161c7c5f52ed348fb1ec683b2b454a83e	Fixed in 7809ac0161c7c5f52ed348fb1ec683b2b454a83e
LinuxLinux	Affected ≥ eba0549bc7d100691c13384b774346b8aa9cf9a9, < 19a1a22029ad3ae3604c763af6bd1195cb73648f	Fixed in 19a1a22029ad3ae3604c763af6bd1195cb73648f
LinuxLinux	Affected =5.18	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: xfs: fix capability check in xfs An user reported a bug where he managed to evade group's quota by changing a file's gid to a different group id the same user belonged to, even though quotas were enforced on both gids and the file's size was big enough to exceed the quota's hardlimit. Commit eba0549bc7d1 replaced a capable() call by a has_capability_noaudit() to prevent unnecessary selinux audit messages. Turns out that both calls have slightly different semantics even though their documentation seems similar. Where in a nutshell: capable() - Tests the task's effective credentials has_ns_capability_noaudit() - Tests the task's real credentials This most of the time has no practical difference but in some cases like changing attrs (specifically group id in this case) through a NFS client this will allow the quota code to use XFS_QMOPT_FORCE_RES, effectively bypassing quota accounting checks. Using instead ns_capable_noaudit() should fix this issue and prevent selinux audit messages. This also fix the remaining calls to has_capability_noaudit()

References

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