---
id: "CVE-2026-122309"
kind: "vulnerability"
aliases: ["CVE-2026-122309"]
title: "Kyverno: namespace policy authors can crash admission controller with CEL expressions"
severity: "high"
cvss: 8.2
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "kubernetes", "kyverno", "self-hosted"]
not_affected_if: ["kyverno-1.19.2-or-later", "no-namespaced-policy-authors"]
published_at: "2026-11-05T03:17:23+00:00"
first_seen_at: "2026-11-05T03:31:41+00:00"
updated_at: "2026-11-05T03:33:23+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-122309", "first_seen_at": "2026-11-05T03:31:41+00:00"}]
exploit_sources: []
---

# Kyverno: namespace policy authors can crash admission controller with CEL expressions

Kyverno before 1.19.2 evaluates CEL expressions in namespace-scoped policies without runtime cost limits. A namespace policy author can use nested map comprehensions over large ConfigMaps to exhaust CPU and memory, get Kyverno pods OOM-killed, and block cluster-wide admission.

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

## How to check

- Check the Kyverno version with `kubectl get deploy -n kyverno kyverno-admission-controller -o jsonpath='{.spec.template.spec.containers[0].image}'`
- Check whether users outside platform teams can create `NamespacedValidatingPolicy` or `NamespacedDeletingPolicy` resources

## Fix

- Kyverno: move to `1.19.2` or later

## Timeline

- 2026-11-05T03:31:41+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-122309

## Documents

- [advisory] Vendor advisory: github.com https://github.com/kyverno/kyverno/security/advisories/GHSA-m8p2-qqmx-j53x
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/kyverno-before-1.19.2-denial-of-service-via-unbounded-cel-policy-evaluation-cost

## From the sources

Kyverno before 1.19.2 contains a denial of service vulnerability that allows namespace-scoped policy authors to exhaust CPU and memory by submitting CEL expressions evaluated without runtime cost limits. Attackers can create a NamespacedValidatingPolicy or NamespacedDeletingPolicy with nested map comprehensions over large ConfigMap fields to OOM-kill Kyverno pods and block cluster-wide admission.

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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_