Kyverno is a policy engine designed for cloud native platform engineering teams. From 1.18.0 until 1.18.2, the NamespacedMutatingPolicy CEL compiler exposes the generator library to matchConditions, allowing a namespace-scoped policy to invoke generator.apply(namespace, resources) with an arbitrary target namespace. The validation in pkg/cel/policies/mpol/validate.go checks that the policy compiles but does not enforce namespace scope, and GenerateResources in pkg/cel/libs/context.go does not reject the cross-namespace target. A user who can create NamespacedMutatingPolicy objects in one namespace can cause the admission controller, operating with cluster-wide privileges, to create ConfigMaps, NetworkPolicies, Secrets, RoleBindings, and other resources in another namespace, enabling unauthorized modification and potential privilege escalation. This issue is fixed in version 1.18.2.

A critical vulnerability exists in Kyverno versions 1.18.0 through 1.18.1 where the NamespacedMutatingPolicy CEL compiler incorrectly exposes the generator library to matchConditions. This allows a namespace-scoped policy to invoke generator.apply() with an arbitrary target namespace, bypassing intended scope restrictions. The root cause lies in pkg/cel/policies/mpol/validate.go failing to enforce namespace scope, and GenerateResources in pkg/cel/libs/context.go not rejecting cross-namespace targets. An attacker with permissions to create NamespacedMutatingPolicy objects in one namespace can exploit the admission controller's cluster-wide privileges to create or modify resources such as ConfigMaps, NetworkPolicies, Secrets, and RoleBindings in other namespaces. This enables unauthorized resource modification and potential privilege escalation across the Kubernetes cluster. The vulnerability has been patched in Kyverno version 1.18.2 with fixes across multiple commits and an SDK update.