---
id: "CVE-2026-13322"
kind: "vulnerability"
aliases: ["CVE-2026-13322", "GHSA-6f2p-2qg2-qqch"]
title: "KubeVirt downward metrics virtio-serial server vulnerable to unbounded memory consumption"
severity: "low"
cvss: 3.8
epss: 0.00134
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "github.com/kubevirt/kubevirt", "fixed": [], "affected": ">= 1.1.0-alpha.0, <= 1.10.0-rc.0", "ecosystem": "go"}, {"name": "redhat openshift virtualization", "fixed": [], "affected": ">= 4, <= 4.22.0", "ecosystem": "vendor"}, {"name": "kubevirt", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["go", "vendor"]
tags: ["cwe-770", "infrastructure", "kubernetes", "kubevirt", "virtualization"]
not_affected_if: ["no-downward-metrics-device", "trusted-guests-only"]
published_at: "2026-06-26T00:16:51+00:00"
first_seen_at: "2026-11-04T17:20:43+00:00"
updated_at: "2026-11-04T17:28:12+00:00"
sources: [{"source": "ghsa", "url": "https://github.com/advisories/GHSA-6f2p-2qg2-qqch", "first_seen_at": "2026-11-04T17:20:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-13322", "first_seen_at": "2026-11-04T17:28:12+00:00"}]
---

# KubeVirt downward metrics virtio-serial server vulnerable to unbounded memory consumption

KubeVirt's downward metrics virtio-serial server reads guest input with no length limit, so it buffers data until a newline arrives. A user inside a VM can stream bytes to that device and make the virt-handler process allocate memory until the kernel kills it.

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

## Affected

- go:github.com/kubevirt/kubevirt affected >= 1.1.0-alpha.0, <= 1.10.0-rc.0 fixed ?
- vendor:redhat openshift virtualization affected >= 4, <= 4.22.0 fixed ?
- vendor:kubevirt affected ? fixed ?

## How to check

- Check the KubeVirt version with `kubectl get kubevirt -n kubevirt -o jsonpath='{.items[0].status.observedKubeVirtVersion}'`
- Check whether any VM sets the downward metrics device: look for `downwardMetrics` under `spec.template.spec.domain.devices` in the VirtualMachine or VirtualMachineInstance objects
- Check the version is in the affected range `>= 1.1.0-alpha.0` and `<= 1.10.0-rc.0`

## Fix

- KubeVirt fixed version: unknown (the sources do not name a fixed release)

## Timeline

- 2026-11-04T17:20:43+00:00 ghsa https://github.com/advisories/GHSA-6f2p-2qg2-qqch
- 2026-11-04T17:28:12+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-13322

## Documents

- [advisory] Vendor advisory: access.redhat.com https://access.redhat.com/security/cve/CVE-2026-13322
- [advisory] Vendor advisory: bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=2492681

## From the sources

A flaw was found in KubeVirt's downward metrics virtio-serial server. The server reads guest requests using textproto.Reader.ReadLine(), which buffers input indefinitely until a newline character is received, with no length limit or read deadline. A user with access to a VM guest that has the downward metrics virtio-serial device configured can write a continuous byte stream to the device, causing unbounded memory allocation in the virt-handler process until it is OOM-killed.

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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_