{"id":"CVE-2026-99131","state":"PUBLISHED","title":"xfs: fix capability check in xfs","description":"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 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()","publishedAt":"2026-10-28T10:34:45.102Z","updatedAt":"2026-10-30T12:42:04.291Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"29f994db0447104a7a52fb6495193c80007cb66a","versionType":"git"},{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"e84bfb08016496ec5ce09a5ef9c813f23c060781","versionType":"git"},{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"87881f816ab721d8a727cba20c36b9c71b489c8e","versionType":"git"},{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"19a1a22029ad3ae3604c763af6bd1195cb73648f","versionType":"git"},{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"7809ac0161c7c5f52ed348fb1ec683b2b454a83e","versionType":"git"},{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"e2f62a9744ebad3bcb6347a648e615026e9efeff","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/xfs/xfs_fsmap.c","fs/xfs/xfs_ioctl.c","fs/xfs/xfs_iops.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/xfs/xfs_fsmap.c","fs/xfs/xfs_ioctl.c","fs/xfs/xfs_iops.c"]}],"references":["https://git.kernel.org/stable/c/29f994db0447104a7a52fb6495193c80007cb66a","https://git.kernel.org/stable/c/e84bfb08016496ec5ce09a5ef9c813f23c060781","https://git.kernel.org/stable/c/87881f816ab721d8a727cba20c36b9c71b489c8e","https://git.kernel.org/stable/c/19a1a22029ad3ae3604c763af6bd1195cb73648f","https://git.kernel.org/stable/c/7809ac0161c7c5f52ed348fb1ec683b2b454a83e","https://git.kernel.org/stable/c/e2f62a9744ebad3bcb6347a648e615026e9efeff"],"weaknesses":[],"ingestedAt":"2026-10-30T13:02:04.640Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/99xxx/CVE-2026-99131.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99131","state":"PUBLISHED","datePublished":"2026-10-28T10:34:45.102Z","dateUpdated":"2026-10-30T12:42:04.291Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.394Z"},"containers":{"cna":{"title":"xfs: fix capability check in xfs","descriptions":[{"lang":"en","value":"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 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()"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"29f994db0447104a7a52fb6495193c80007cb66a","versionType":"git"},{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"e84bfb08016496ec5ce09a5ef9c813f23c060781","versionType":"git"},{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"87881f816ab721d8a727cba20c36b9c71b489c8e","versionType":"git"},{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"19a1a22029ad3ae3604c763af6bd1195cb73648f","versionType":"git"},{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"7809ac0161c7c5f52ed348fb1ec683b2b454a83e","versionType":"git"},{"version":"eba0549bc7d100691c13384b774346b8aa9cf9a9","status":"affected","lessThan":"e2f62a9744ebad3bcb6347a648e615026e9efeff","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/xfs/xfs_fsmap.c","fs/xfs/xfs_ioctl.c","fs/xfs/xfs_iops.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/xfs/xfs_fsmap.c","fs/xfs/xfs_ioctl.c","fs/xfs/xfs_iops.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/29f994db0447104a7a52fb6495193c80007cb66a"},{"url":"https://git.kernel.org/stable/c/e84bfb08016496ec5ce09a5ef9c813f23c060781"},{"url":"https://git.kernel.org/stable/c/87881f816ab721d8a727cba20c36b9c71b489c8e"},{"url":"https://git.kernel.org/stable/c/19a1a22029ad3ae3604c763af6bd1195cb73648f"},{"url":"https://git.kernel.org/stable/c/7809ac0161c7c5f52ed348fb1ec683b2b454a83e"},{"url":"https://git.kernel.org/stable/c/e2f62a9744ebad3bcb6347a648e615026e9efeff"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:42:04.291Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.6.161"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.12.115"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.18.59"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"7.2.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}