Kyverno before v1.13.4 is vulnerable to server-side request forgery (SSRF) via its Service Call functionality. An attacker with permission to create Kyverno (Cluster)Policies can specify an external URL in a policy's apiCall/service configuration; although Service Call is documented for in-cluster services, it also resolves external addresses, allowing requests to an attacker-controlled server. Because policy context data (including contents of Kubernetes resources such as secrets) is sent in these requests, an attacker can exfiltrate sensitive cluster data.