Auth bypass in Kyverno
CVE-2026-122303
Kyverno from 1.17.0 before 1.19.2 contains an authorization bypass vulnerability that allows namespace tenants to overwrite resources in other namespaces via NamespacedMutatingPolicy mutate-existing targetMatchConstraints.expression. Attackers can return a CEL map literal fabricating a target with an attacker-chosen metadata.namespace, causing the privileged background controller to overwrite Secrets, Deployments, or policies cluster-wide.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- GitHub Security Advisory (GHSA-jcw5-3wcg-fqx5) (vendor-advisory)
- VulnCheck Advisory: Kyverno 1.17.0 before 1.19.2 Cross-Namespace Resource Overwrite via NamespacedMutatingPolicy (third-party-advisory)
Frequently asked questions
- What is CVE-2026-122303?
- CVE-2026-122303 is a critical-severity vulnerability in Kyverno, classified under Missing Authorization. CVSS score: 9.9/10. Published 2026-11-05.
- How severe is CVE-2026-122303?
- Critical severity. CVSS v3 base score is 9.9 out of 10.