CVE-2026-27456
- Source
- https://cve.org/CVERecord?id=CVE-2026-27456
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27456.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-27456
- Aliases
-
- GHSA-qq4x-vfq4-9h9g
- Downstream
- Related
- Published
- 2026-04-03T21:23:00.984Z
- Modified
- 2026-07-08T08:12:48.239268Z
- Severity
-
- 4.7 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N CVSS Calculator
- Summary
- util-linux: TOCTOU Race Condition in util-linux mount(8) - Loop Device Setup
- Details
-
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.
- Database specific
{ "cna_assigner": "GitHub_M", "cwe_ids": [ "CWE-269", "CWE-367", "CWE-59" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27456.json" }- References
-
- https://github.com/util-linux/util-linux/releases/tag/v2.41.4
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27456.json
- https://github.com/util-linux/util-linux/security/advisories/GHSA-qq4x-vfq4-9h9g
- https://nvd.nist.gov/vuln/detail/CVE-2026-27456
- https://github.com/util-linux/util-linux/commit/5e390467b26a3cf3fecc04e1a0d482dff3162fc4
Affected packages
Git / github.com/util-linux/util-linux
Affected ranges
- Type
- GIT
- Repo
- https://github.com/util-linux/util-linux
- Events
-
Introduced0 Unknown introduced commit / All previous commits are affectedFixedFixed
- Database specific
{ "extracted_events": [ { "introduced": "0" }, { "fixed": "2.41.4" } ], "cpe": "cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:*", "source": [ "CPE_RANGE", "REFERENCES" ] }