CVE-2026-13218

Kubevirt: kubevirt: symlink following in writetocachedfile allows host file overwrite from virt-launcher

Published Jun 25, 2026 CVSS 3.1 · 4.2 Medium EPSS < 1% KEV · Not listed
Description
A flaw was found in KubeVirt's virt-handler network cache handling. The WriteToCachedFile function writes data to a launcher-rooted path using os.WriteFile and os.Chown without symlink protection. A user with access to the virt-launcher container can plant a symlink at the cache file path, causing virt-handler to follow it and overwrite an arbitrary host file with JSON content and change its ownership.

Remediation

Vendor Workaround

Ensure virtual machines use the default masquerade network binding mode where possible. Restrict pods/exec access on virt-launcher pods to only trusted administrators. Review and restrict NetworkAttachmentDefinition resources to limit which namespaces can configure bridge-type network interfaces.

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-q3jc-42cq-33fj KubeVirt virt-handler network cache symlink vulnerability allows arbitrary host file overwrite
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Kubevirt
Kubevirt kubevirt
Redhat openshift Virtualization
Vendors & Products Kubevirt
Kubevirt kubevirt
Redhat openshift Virtualization
Type Values Removed Values Added
Description A flaw was found in KubeVirt's virt-handler network cache handling. The WriteToCachedFile function writes data to a launcher-rooted path using os.WriteFile and os.Chown without symlink protection. A user with access to the virt-launcher container can plant a symlink at the cache file path, causing virt-handler to follow it and overwrite an arbitrary host file with JSON content and change its ownership.
Title Kubevirt: kubevirt: symlink following in writetocachedfile allows host file overwrite from virt-launcher
First Time appeared Redhat
Redhat container Native Virtualization
Weaknesses CWE-61
CPEs cpe:/a:redhat:container_native_virtualization:4
Vendors & Products Redhat
Redhat container Native Virtualization
References
Metrics cvssV3_1

{'score': 4.2, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:L'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Jun 26, 2026, 2:58 PM
Reserved
Jun 24, 2026, 3:29 PM
Status
Analyzed
Published
Jun 26, 2026, 12:16 AM
Modified
Oct 25, 2026, 10:10 PM
Severity
Moderate
Public date
Jun 25, 2026, 12:00 AM