CVE-2026-77159

Libvirt: unsafe chown in qemutpmemulatorpreparehost() allows arbitrary file ownership change via symlink

MEDIUM
5.5
CVSS Score
Published: September 11, 2026 at 10:32 AM UTC
Updated: September 16, 2026 at 07:54 PM UTC
1 product affected across 1 vendorEnterprise Linux

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Vendor states this is fixed in 6 (unaffected)
Vendor states this is fixed in 7 (unknown)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (3)

VDB Entryx_refsource_REDHAT
Source: cverecord
https://access.redhat.com/security/cve/CVE-2026-77159
Issue Trackingx_refsource_REDHAT
Source: cverecord
https://bugzilla.redhat.com/show_bug.cgi?id=2531811

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.5MEDIUMredhat
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-61

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