{"id":"CVE-2026-53612","state":"PUBLISHED","title":"util-linux mount hook_owner TOCTOU allows local privilege escalation","description":"util-linux is a random collection of Linux utilities. In util-linux 2.39 through 2.41.4 and 2.42 through 2.42.1, the SUID `mount` utility's `hook_owner.c` post-mount hook performs path-based `chmod()` and `lchown()` operations on a previously validated mount target. A local low-privileged user authorized by an `/etc/fstab` entry with `user` or `users` and an `X-mount.mode`, `X-mount.owner`, or `X-mount.group` option can use `renameat2(RENAME_EXCHANGE)` to race a writable ancestor of the target and redirect the privileged ownership or mode change to a root-owned path, potentially gaining root privileges. This issue is fixed in 2.41.5 and 2.42.2.","publishedAt":"2026-10-14T14:47:25.523Z","updatedAt":"2026-10-14T18:26:36.386Z","severity":{"score":7,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["util-linux util-linux"],"affected":[{"vendor":"util-linux","product":"util-linux","versions":[{"version":">= 2.39, < 2.41.5","status":"affected"},{"version":">= 2.42, < 2.42.2","status":"affected"}]}],"references":["https://github.com/util-linux/util-linux/security/advisories/GHSA-g8wm-75wr-g2vh","https://github.com/util-linux/util-linux/commit/24da33905c7115c4cbccd0afb2a469804e96467a","https://github.com/util-linux/util-linux/commit/722c96974dd4009a334e4aee556eedaab5fb94b4","https://github.com/util-linux/util-linux/commit/897a08c2b11dfa66975c3d24d63c7bf5f5be1a7c","https://github.com/util-linux/util-linux/commit/d0c5adaeb3a3d823aba1377794de8f009b8152cc","https://github.com/util-linux/util-linux/releases/tag/v2.41.5","https://github.com/util-linux/util-linux/releases/tag/v2.42.2"],"weaknesses":["CWE-367"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53612.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53612","state":"PUBLISHED","datePublished":"2026-10-14T14:47:25.523Z","dateUpdated":"2026-10-14T18:26:36.386Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-09T19:39:52.405Z"},"containers":{"cna":{"title":"util-linux mount hook_owner TOCTOU allows local privilege escalation","descriptions":[{"lang":"en","value":"util-linux is a random collection of Linux utilities. In util-linux 2.39 through 2.41.4 and 2.42 through 2.42.1, the SUID `mount` utility's `hook_owner.c` post-mount hook performs path-based `chmod()` and `lchown()` operations on a previously validated mount target. A local low-privileged user authorized by an `/etc/fstab` entry with `user` or `users` and an `X-mount.mode`, `X-mount.owner`, or `X-mount.group` option can use `renameat2(RENAME_EXCHANGE)` to race a writable ancestor of the target and redirect the privileged ownership or mode change to a root-owned path, potentially gaining root privileges. This issue is fixed in 2.41.5 and 2.42.2."}],"affected":[{"vendor":"util-linux","product":"util-linux","versions":[{"version":">= 2.39, < 2.41.5","status":"affected"},{"version":">= 2.42, < 2.42.2","status":"affected"}]}],"references":[{"url":"https://github.com/util-linux/util-linux/security/advisories/GHSA-g8wm-75wr-g2vh","name":"https://github.com/util-linux/util-linux/security/advisories/GHSA-g8wm-75wr-g2vh","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/util-linux/util-linux/commit/24da33905c7115c4cbccd0afb2a469804e96467a","name":"https://github.com/util-linux/util-linux/commit/24da33905c7115c4cbccd0afb2a469804e96467a","tags":["x_refsource_MISC"]},{"url":"https://github.com/util-linux/util-linux/commit/722c96974dd4009a334e4aee556eedaab5fb94b4","name":"https://github.com/util-linux/util-linux/commit/722c96974dd4009a334e4aee556eedaab5fb94b4","tags":["x_refsource_MISC"]},{"url":"https://github.com/util-linux/util-linux/commit/897a08c2b11dfa66975c3d24d63c7bf5f5be1a7c","name":"https://github.com/util-linux/util-linux/commit/897a08c2b11dfa66975c3d24d63c7bf5f5be1a7c","tags":["x_refsource_MISC"]},{"url":"https://github.com/util-linux/util-linux/commit/d0c5adaeb3a3d823aba1377794de8f009b8152cc","name":"https://github.com/util-linux/util-linux/commit/d0c5adaeb3a3d823aba1377794de8f009b8152cc","tags":["x_refsource_MISC"]},{"url":"https://github.com/util-linux/util-linux/releases/tag/v2.41.5","name":"https://github.com/util-linux/util-linux/releases/tag/v2.41.5","tags":["x_refsource_MISC"]},{"url":"https://github.com/util-linux/util-linux/releases/tag/v2.42.2","name":"https://github.com/util-linux/util-linux/releases/tag/v2.42.2","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"LOCAL","availabilityImpact":"HIGH","baseScore":7,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-367","lang":"en","description":"CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-14T14:47:25.523Z"},"source":{"advisory":"GHSA-g8wm-75wr-g2vh","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/util-linux/util-linux/security/advisories/GHSA-g8wm-75wr-g2vh","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-14T18:24:31.298549Z","id":"CVE-2026-53612","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-14T18:26:36.386Z"}}]}}}