Medium [CVE-2026-77159] Unsafe chown in qemuTPMEmulatorPrepareHost allows arbitrary file ownership change via symlink
This medium-severity Red Hat Linux advisory covers CVE-2026-77159 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8.
Android app · Google Play
Monitor future Red Hat Linux CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.
Summary
A symlink-following flaw was found in libvirt's qemuTPMEmulatorPrepareHost() function. The function uses a path-based chown() on the swtpm logfile without checking for symbolic links.
A local attacker with access to the swtpm account can replace the logfile with a symlink, causing libvirtd (running as root) to transfer ownership of an arbitrary file to the swtpm user. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N).
Weakness: CWE-61. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9.
Will not fix / out of support: Red Hat Enterprise Linux 7. Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: libvirt.
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 13 minutes ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 13 minutes ago·verify at source
Mitigation checklist
- On Red Hat Enterprise Linux, SELinux in enforcing mode (the default) confines the swtpm process to the swtpm_t domain, which restricts the creation of symlinks to arbitrary file types and limits the scope of any ownership change, reducing the practical impact of this flaw. Ensure SELinux is not disabled or set to permissive mode.
Official advisory · high-confidence parse· fetched 13 minutes ago·verify at source
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.