{"id":"CVE-2026-122303","published":"2026-11-05T03:17:22.197","lastModified":"2026-11-05T03:17:22.197","description":"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.","cvssScore":9.9,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","cwes":["CWE-862"],"vendors":[],"products":[],"references":[{"url":"https://github.com/kyverno/kyverno/security/advisories/GHSA-jcw5-3wcg-fqx5","tags":[]},{"url":"https://www.vulncheck.com/advisories/kyverno-1.17.0-before-1.19.2-cross-namespace-resource-overwrite-via-namespacedmutatingpolicy","tags":[]}],"exploitRefs":[{"url":"https://github.com/kyverno/kyverno/security/advisories/GHSA-jcw5-3wcg-fqx5","tags":[]}],"hasPoc":true,"ai":{"summary":"Kyverno versions before 1.19.2 contain an authorization bypass (CWE-862) in NamespacedMutatingPolicy with mutate-existing targetMatchConstraints.expression, allowing namespace-scoped users to forge target resource namespaces via CEL map literals, enabling cross-namespace or cluster-wide overwrites of sensitive resources like Secrets and Deployments.","exploitability":"Exploitation requires low privilege (PR:L) and no user interaction (UI:N), but is limited to attackers with access to create or modify NamespacedMutatingPolicies in their own namespace.","blast_radius":"Successful exploitation allows cluster-wide resource overwrites, potentially compromising confidentiality, integrity, and availability across the entire Kubernetes cluster.","remediation":"Upgrade to Kyverno 1.19.2 or later.","detection":"Monitor for NamespacedMutatingPolicy resources containing mutate-existing targetMatchConstraints.expression that return a CEL map literal with a fabricated metadata.namespace field; such policies may indicate an attempt to bypass namespace isolation.","tags":["auth-bypass","kubernetes","kyverno","cel-injection","privilege-escalation","cluster-wide"],"model":"garnet-coder","analyzedAt":"2026-11-05T09:44:20.572Z"}}