Kyverno before 1.19.2 Denial of Service via Unbounded CEL Policy Evaluation Cost

Summary

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.

Remediation

1. Inventory every kyverno kyverno deployment, including staging.
2. Upgrade kyverno kyverno to 1.19.2.
3. Confirm the running version after the upgrade.

References

• Advisoryhttps://github.com/kyverno/kyverno/security/advisories/GHSA-m8p2-qqmx-j53x
• Advisoryhttps://www.vulncheck.com/advisories/kyverno-before-1.19.2-denial-of-service-via-unbounded-cel-policy-evaluation-cost