CVE-2026-77159 Libvirt: unsafe chown in qemutpmemulatorpreparehost() allows arbitrary file ownership change via symlink
A local attacker can exploit a symlink flaw in libvirt's TPM emulator to change ownership of arbitrary files, potentially leading to privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-77159?
CVE-2026-77159 is a medium-severity path traversal vulnerability in Red Hat Enterprise Linux 10, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-61
Which versions are affected by CVE-2026-77159?
How do I fix CVE-2026-77159?
Apply the vendor's patch.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-77159 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-77159 exists.
Sources
Also known as AZL-101739, BELL-CVE-2026-77159, DEBIAN-CVE-2026-77159, GHSA-wmhq-5pq5-8474, OESA-2026-4059, UBUNTU-CVE-2026-77159.