CVE-2026-13218: Kubevirt: kubevirt: symlink following in writetocachedfile allows host file overwrite from virt-launcher

Severity: medium (CVSS 4.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-26 · updated 2026-10-25
Weakness: CWE-61

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 products

kubevirt: all versions
RedHat Openshift Virtualization: from 4 through 4.22.0

References

https://access.redhat.com/security/cve/CVE-2026-13218
https://bugzilla.redhat.com/show_bug.cgi?id=2492654

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