CVE-2026-77159
libvirt: Unsafe chown in qemuTPMEmulatorPrepareHost() allows arbitrary file ownership change via symlink
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · September 11, 2026
Updated · September 11, 2026
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.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
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.
CVSS / CWE
CVSS 3.1 · 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
CWE-61 · UNIX Symbolic Link (Symlink) Following