---
id: "CVE-2026-13218"
kind: "vulnerability"
aliases: ["CVE-2026-13218", "GHSA-q3jc-42cq-33fj"]
title: "KubeVirt virt-handler network cache symlink vulnerability allows arbitrary host file overwrite"
severity: "medium"
cvss: 4.2
epss: 0.00139
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "kubevirt.io/kubevirt", "fixed": [], "affected": "<= 1.10.0-rc.0", "ecosystem": "go"}, {"name": "kubevirt", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "redhat openshift virtualization", "fixed": [], "affected": ">= 4, <= 4.22.0", "ecosystem": "vendor"}]
ecosystems: ["go", "vendor"]
tags: ["cwe-61", "infrastructure", "kubernetes", "kubevirt", "virtualization"]
not_affected_if: ["no-untrusted-vm-users", "version-above-affected-range"]
published_at: "2026-06-26T00:16:51+00:00"
first_seen_at: "2026-11-04T17:25:52+00:00"
updated_at: "2026-11-04T17:28:12+00:00"
sources: [{"source": "ghsa", "url": "https://github.com/advisories/GHSA-q3jc-42cq-33fj", "first_seen_at": "2026-11-04T17:25:52+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-13218", "first_seen_at": "2026-11-04T17:28:12+00:00"}]
---

# KubeVirt virt-handler network cache symlink vulnerability allows arbitrary host file overwrite

KubeVirt's virt-handler writes network cache files without checking for symlinks, so a user in the virt-launcher container can plant a symlink and make virt-handler overwrite an arbitrary host file. The attacker also controls the file's ownership change, which can be used to break host integrity.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- go:kubevirt.io/kubevirt affected <= 1.10.0-rc.0 fixed ?
- vendor:kubevirt affected ? fixed ?
- vendor:redhat openshift virtualization affected >= 4, <= 4.22.0 fixed ?

## How to check

- Check the installed KubeVirt version with `kubectl get kubevirt -n kubevirt -o jsonpath='{.items[0].status.observedKubeVirtVersion}'`
- Compare against the affected range: `go:kubevirt.io/kubevirt` up to and including `1.10.0-rc.0`

## Timeline

- 2026-11-04T17:25:52+00:00 ghsa https://github.com/advisories/GHSA-q3jc-42cq-33fj
- 2026-11-04T17:28:12+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-13218

## Documents

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

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_