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UK Cyber Defence
VulnerabilityAwaiting Analysis

CVE-2026-77159

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.

MEDIUM 5.5EPSS 0.16%

Does this matter?

Lower severity and a low EPSS score (0.16%). Track it; it rarely justifies an emergency change on its own.

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 3.1
5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
EPSS
0.16% probability · 5th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-61
Source
secalert@redhat.com
EPSS trend
0%3%5%26 October 2026: 0.16%26 October 202626 October 2026

EPSS 0.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.