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
EPSS: 0.003 (26.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 26.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
The 30-day trend appears once there are two daily scores.
Affected products
Weakness classification (CWE)
References
- github.com/kyverno/kyverno/security/advisories/GHSA-jcw5-3wcg-fqx5 (vendor-advisory)
- www.vulncheck.com/advisories/kyverno-1.17.0-before-1.19.2-cross-namespace-resou… (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.