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.
Problem types
UNIX Symbolic Link (Symlink) Following
Product status
Timeline
| 2026-06-24: | Reported to Red Hat. |
| 2026-06-25: | Made public. |
Credits
This issue was discovered by Huzaifa Sidhpurwala (Red Hat).
References
access.redhat.com/security/cve/CVE-2026-13218
bugzilla.redhat.com/show_bug.cgi?id=2492654 (RHBZ#2492654)