Kyverno before version 1.13.4 is vulnerable to server‑side request forgery (CWE-918) through its Service Call feature. An attacker who can create Kyverno (Cluster)Policies can specify an external URL in a policy’s apiCall/service configuration. Although Service Call is intended for in‑cluster services, it resolves external addresses, enabling the policy to send an HTTP request to an attacker‑controlled server. The request includes policy context data, such as the contents of Kubernetes resources and secrets, allowing exfiltration of confidential cluster information.

All Kyverno Kyverno installations prior to v1.13.4 are affected. The vulnerable functionality is present in every version of Kyverno up to and including 1.13.3.

The vulnerability has a CVSS score of 6.9, indicating a moderate severity. EPSS is not available, so the likelihood of exploitation is currently unknown. The CVE is not listed in the CISA KEV catalog. The attack requires the attacker to have permission to create Kyverno policies, which is a privilege that may be limited in well‑guarded clusters. Once this privilege is obtained, the attacker can use the Service Call to reach any external address and exfiltrate data.