Kyverno versions 1.16.0 through 1.19.1 fail to validate path components in the resource argument of resource.get() and resource.post(). This omission allows a namespaced CEL policy to include .. segments that escape its namespace, enabling the policy to read and write arbitrary cluster objects through the admission controller’s ServiceAccount. The result is an ability to compromise the entire cluster, effectively achieving cluster takeover.

Affected systems are Kyverno deployments running any version from 1.16.0 up to and including 1.19.1. The vulnerability exists in the Kyverno product. Administrators should verify the current version in use and plan an upgrade to 1.19.2 or later.

The CVSS score of 9.4 marks this flaw as critical, and although no EPSS value is provided, the absence from CISA’s KEV catalog suggests limited public exploitation. The likely attack vector involves an actor with permission to create NamespacedValidatingPolicy objects inserting path traversal fragments; such a policy then gains unauthorized access via the admission controller’s ServiceAccount, potentially granting cluster‑wide privileges.