CVE-2026-77159

Publication date 11 September 2026

Last updated 28 September 2026

Ubuntu priority

Cvss 3 Severity Score

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.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libvirt	26.10 stonking	Not affected
	26.04 LTS resolute	Fixed in 12.0.0-1ubuntu5.5
	24.04 LTS noble	Fixed in 10.0.0-2ubuntu8.19
	22.04 LTS jammy	Fixed in 8.0.0-1ubuntu7.21
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Needs evaluation
libvirt-hwe	26.10 stonking	Not affected
	26.04 LTS resolute	Fixed in 12.0.0-1ubuntu5.5
	24.04 LTS noble	Not in release
	22.04 LTS jammy	Not in release

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
libvirt	Upstream: 68e03ee

Severity score breakdown

CVSS version: CVSS v3.0

Base score 5.5 · Medium

Base metrics

Parameter	Value
Attack vector	Local
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality impact	None
Integrity impact	High
Availability impact	None

Scores

Parameter	Value
Base score	5.5 · Medium
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

References

Related Ubuntu Security Notices (USN)

USN-8831-1
libvirt vulnerabilities
28 September 2026

USN-8833-1
libvirt vulnerabilities
28 September 2026