{"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": "2026-04-03T21:23:00.984Z"}, "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"}}}}

{}

{"cveTags": [], "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."}], "id": "CVE-2026-27456", "lastModified": "2026-04-03T22:16:25.400", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 1.0, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-04-03T22:16:25.400", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/util-linux/util-linux/commit/5e390467b26a3cf3fecc04e1a0d482dff3162fc4"}, {"source": "security-advisories@github.com", "url": "https://github.com/util-linux/util-linux/releases/tag/v2.41.4"}, {"source": "security-advisories@github.com", "url": "https://github.com/util-linux/util-linux/security/advisories/GHSA-qq4x-vfq4-9h9g"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-59"}, {"lang": "en", "value": "CWE-269"}, {"lang": "en", "value": "CWE-367"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{}