Medium [CVE-2026-19079] toctou race condition in fixfiles allows arbitrary selinux label manipulation
This medium-severity Red Hat Linux advisory covers CVE-2026-19079 affecting Red Hat Hardened Images, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6.
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Summary
A TOCTOU (Time-of-Check-Time-of-Use) race condition vulnerability was found in the fixfiles script in policycoreutils. When running fixfiles relabel or fixfiles restore, the script used find and chcon commands to locate and relabel unlabeled files under /tmp and other directories.
A local attacker could exploit a race window between the file discovery and the label change operation by swapping directory components with symlinks, causing chcon to follow the symlink and modify SELinux labels on arbitrary system files. This could undermine SELinux mandatory access control protections on critical files such as /etc/shadow.
Red Hat ships policycoreutils with the fixfiles script in all supported RHEL versions. The vulnerable /tmp cleanup code path has been present in fixfiles for many years.
Red Hat product impact analysis is required to determine which specific shipped versions of policycoreutils include the vulnerable code and whether backporting the upstream fix is necessary.
The vulnerability requires local access, winning a race condition, and an administrator running fixfiles relabel or fixfiles restore, which limits the practical attack surface. Red Hat severity: Moderate — CVSS 4.4 (CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N).
Weakness: CWE-367.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
- policycoreutils-main-3.11-2.2.hum1
- RHSA-2026:51861
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
Mitigation checklist
- As a workaround, use 'restorecon -R /' directly instead of 'fixfiles relabel' or 'fixfiles restore' to perform filesystem relabeling. This avoids the vulnerable /tmp-specific find+chcon code path entirely. Note that this skips the /tmp cleanup logic, but on modern systems where /tmp is mounted as tmpfs, this cleanup is unnecessary as tmpfs cannot retain files from a prior boot.
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
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