{"id":"CVE-2026-99131","title":"xfs: fix capability check in xfs","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfs: fix capability check in xfs\n\nAn user reported a bug where he managed to evade group's quota\nby changing a file's gid to a different group id the same user\nbelonged…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= eba0549bc7d100691c13384b774346b8aa9cf9a9 < 19a1a22029ad3ae3604c763af6bd1195cb73648f","Linux >= eba0549bc7d100691c13384b774346b8aa9cf9a9 < 7809ac0161c7c5f52ed348fb1ec683b2b454a83e","Linux >= eba0549bc7d100691c13384b774346b8aa9cf9a9 < e2f62a9744ebad3bcb6347a648e615026e9efeff","Linux 5.18"],"published":"2026-10-28","updated":"2026-10-28","sourceUpdated":"2026-10-28T10:34:45.102Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99131","references":[{"url":"https://git.kernel.org/stable/c/19a1a22029ad3ae3604c763af6bd1195cb73648f"},{"url":"https://git.kernel.org/stable/c/7809ac0161c7c5f52ed348fb1ec683b2b454a83e"},{"url":"https://git.kernel.org/stable/c/e2f62a9744ebad3bcb6347a648e615026e9efeff"}],"tags":["cve.org"],"ingestedAt":"2026-10-28T11:09:40.436Z","slug":"CVE-2026-99131","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nxfs: fix capability check in xfs\n\nAn user reported a bug where he managed to evade group's quota\nby changing a file's gid to a different group id the same user\nbelonged to, even though quotas were enforced on both gids and the\nfile's size was big enough to exceed the quota's hardlimit.\n\nCommit eba0549bc7d1 replaced a capable() call by a\nhas_capability_noaudit() to prevent unnecessary selinux audit messages.\nTurns out that both calls have slightly different semantics even though\ntheir documentation seems similar. Where in a nutshell:\n\ncapable() - Tests the task's effective credentials\nhas_ns_capability_noaudit() - Tests the task's real credentials\n\nThis most of the time has no practical difference but in some cases like\nchanging attrs (specifically group id in this case) through a NFS client\nthis will allow the quota code to use XFS_QMOPT_FORCE_RES, effectively\nbypassing quota accounting checks.\n\nUsing instead ns_capable_noaudit() should fix this issue and prevent\nselinux audit messages.\n\nThis also fix the remaining calls to has_capability_noaudit()\n\n## Affected\n\n- `Linux >= eba0549bc7d100691c13384b774346b8aa9cf9a9 < 19a1a22029ad3ae3604c763af6bd1195cb73648f`\n- `Linux >= eba0549bc7d100691c13384b774346b8aa9cf9a9 < 7809ac0161c7c5f52ed348fb1ec683b2b454a83e`\n- `Linux >= eba0549bc7d100691c13384b774346b8aa9cf9a9 < e2f62a9744ebad3bcb6347a648e615026e9efeff`\n- `Linux 5.18`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}