GHSA-qr4g-8hrp-c4rw: Kyverno has unrestricted outbound requests in Kyverno apiCall enabling SSRF

A Server-Side Request Forgery (SSRF) vulnerability in Kyverno allows authenticated users to induce the admission controller to send arbitrary HTTP requests to attacker-controlled endpoints.

When a ClusterPolicy uses apiCall.service.url with variable substitution (e.g. {{request.object.*}}), user-controlled input can influence the request target. The Kyverno admission controller executes these requests from its privileged network position without enforcing any validation or network restrictions.

The issue becomes non-blind SSRF, as response data from internal services can be reflected back to the user via admission error messages.