Kyverno versions starting from 1.19.1 and up to but excluding 1.19.2 contain a flaw in the APICall Fetch() method. The underlying path.Clean routine incorrectly treats the '?' character as a literal path component, allowing the namespace regular expression to match query string segments. As a result, a user who can create namespaced policies can supply an API call such as /api/v1/nodes?x=/namespaces/default/, which passes policy validation yet causes the client‑go library to hit a cluster‑scoped endpoint. This bypass grants read access to resources outside the user’s namespace, exposing potentially sensitive data.

Kyverno deployed in Kubernetes clusters. The vulnerability specifically affects only the 1.19.1 release. Versions prior to 1.19.1 and 1.19.2 or later are not impacted.

The CVSS score of 8.3 classifies the issue as high severity. The EPSS score is not available, and the vulnerability is not listed in the CISA KEV catalog, suggesting limited evidence of real‑world exploitation at this time. Nevertheless, the flaw is exploitable over the network through normal Kubernetes API traffic, and it requires only the ability to author a namespaced policy. An attacker with that privilege can bypass namespace isolation, read non‑authorized cluster resources, and potentially compromise data confidentiality at the cluster layer.