CVE-2026-54523

Name of the Vulnerable Software and Affected Versions Kyverno versions 1.18.0 through 1.18.1

Description In the NamespacedMutatingPolicy CEL compiler, the generator library is exposed to matchConditions, allowing a namespace-scoped policy to invoke the generator.apply(namespace, resources) function with an arbitrary target namespace. The validation process in pkg/cel/policies/mpol/validate.go only verifies that the policy compiles without enforcing namespace scope, and the GenerateResources() function in pkg/cel/libs/context.go fails to reject cross-namespace targets.

A user with permissions to create NamespacedMutatingPolicy objects in a specific namespace can exploit this to force the admission controller, which operates with cluster-wide privileges, to create resources such as ConfigMaps, NetworkPolicies, Secrets, and RoleBindings in any other namespace. This can lead to unauthorized modification of protected namespaces (e.g., kube-system) and potential privilege escalation to cluster administrator levels.

Recommendations Update Kyverno to version 1.18.2. As a temporary mitigation, restrict user permissions to prevent non-admin users from creating NamespacedMutatingPolicy objects.