{"id":"CVE-2026-27456","title":"util-linux is a random collection of Linux utilities","summary":"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 lo…","severity":"medium","cvss":4.7,"cvssVector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-59","CWE-269","CWE-367"],"vendor":"kernel","product":"util-linux","affected":["util-linux < 2.41.4"],"patched":["util-linux 2.41.4"],"published":"2026-04-03","updated":"2026-07-24","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-27456","references":[{"url":"https://github.com/util-linux/util-linux/commit/5e390467b26a3cf3fecc04e1a0d482dff3162fc4","label":"security-advisories@github.com"},{"url":"https://github.com/util-linux/util-linux/releases/tag/v2.41.4","label":"security-advisories@github.com"},{"url":"https://github.com/util-linux/util-linux/security/advisories/GHSA-qq4x-vfq4-9h9g","label":"security-advisories@github.com"},{"url":"https://github.com/util-linux/util-linux/security/advisories/GHSA-qq4x-vfq4-9h9g","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27456.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-27456"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2454956"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-27456"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27456"},{"url":"https://access.redhat.com/errata/RHSA-2026:7180"}],"tags":["nvd","csaf","vex","red-hat"],"epss":0.00118,"epssPercentile":0.01946,"ingestedAt":"2026-07-25T22:05:05.013Z","slug":"CVE-2026-27456","body":"## Overview\n\nutil-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.\n\n## Affected\n\n- `util-linux < 2.41.4`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `util-linux 2.41.4`\n\n## Vendor advisories\n\n- **RHSA-2026:7180** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-04-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:7180)\n- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4, Red Hat Enterprise Linux 10 · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27456.json)","depth":"sunlit","depthScore":26,"depthScoreParts":{"impact":25.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}