{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-27456","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-02-19T17:25:31.100Z","datePublished":"2026-04-03T21:23:00.984Z","dateUpdated":"2026-04-06T15:42:35.774Z"},"containers":{"cna":{"title":"util-linux: TOCTOU Race Condition in util-linux mount(8) - Loop Device Setup","problemTypes":[{"descriptions":[{"cweId":"CWE-59","lang":"en","description":"CWE-59: Improper Link Resolution Before File Access ('Link Following')","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-269","lang":"en","description":"CWE-269: Improper Privilege Management","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-367","lang":"en","description":"CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"LOCAL","availabilityImpact":"NONE","baseScore":4.7,"baseSeverity":"MEDIUM","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/util-linux/util-linux/security/advisories/GHSA-qq4x-vfq4-9h9g","tags":["x_refsource_CONFIRM"],"url":"https://github.com/util-linux/util-linux/security/advisories/GHSA-qq4x-vfq4-9h9g"},{"name":"https://github.com/util-linux/util-linux/commit/5e390467b26a3cf3fecc04e1a0d482dff3162fc4","tags":["x_refsource_MISC"],"url":"https://github.com/util-linux/util-linux/commit/5e390467b26a3cf3fecc04e1a0d482dff3162fc4"},{"name":"https://github.com/util-linux/util-linux/releases/tag/v2.41.4","tags":["x_refsource_MISC"],"url":"https://github.com/util-linux/util-linux/releases/tag/v2.41.4"}],"affected":[{"vendor":"util-linux","product":"util-linux","versions":[{"version":"< 2.41.4","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-04-03T21:23:00.984Z"},"descriptions":[{"lang":"en","value":"util-linux is a random collection of Linux utilities. Prior to version 2.41.4, a TOCTOU (Time-of-Check-Time-of-Use) vulnerability has been identified in the SUID binary /usr/bin/mount from util-linux. The mount binary, when setting up loop devices, validates the source file path with user privileges via fork() + setuid() + realpath(), but subsequently re-canonicalizes and opens it with root privileges (euid=0) without verifying that the path has not been replaced between both operations. Neither O_NOFOLLOW, nor inode comparison, nor post-open fstat() are employed. This allows a local unprivileged user to replace the source file with a symlink pointing to any root-owned file or device during the race window, causing the SUID binary to open and mount it as root. Exploitation requires an /etc/fstab entry with user,loop options whose path points to a directory where the attacker has write permission, and that /usr/bin/mount has the SUID bit set (the default configuration on virtually all Linux distributions). The impact is unauthorized read access to root-protected files and block devices, including backup images, disk volumes, and any file containing a valid filesystem. This issue has been patched in version 2.41.4."}],"source":{"advisory":"GHSA-qq4x-vfq4-9h9g","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/util-linux/util-linux/security/advisories/GHSA-qq4x-vfq4-9h9g","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-06T15:38:42.794607Z","id":"CVE-2026-27456","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-04-06T15:42:35.774Z"}}]}}