CVE-2026-13218 — kubevirt
MEDIUMCVE-2026-13218 is a medium-severity (CVSS 4.2) CWE-61 vulnerability in kubevirt.io/kubevirt. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.
KubeVirt virt-handler network cache symlink vulnerability allows arbitrary host file overwrite
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-13218.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
kubevirt.io/kubevirtReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | kubevirt.io/kubevirt | all versions | No fix |
Affected Products
kubevirtkubevirtopenshift virtualizationredhatDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for kubevirt.io/kubevirt, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
The records we use list no patched version of kubevirt.io/kubevirt for CVE-2026-13218. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This flaw affects OpenShift Virtualization deployments where virtual machines are configured with bridge or other non-masquerade network interfaces. The default network binding mode in OpenShift Virtualization is masquerade, which does not trigger the vulnerable code path — exploitation requires a cluster…
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.Source: Red Hat security advisory for CVE-2026-13218 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-13218 in your dependencies?
Find it across Go, including transitive dependencies.