MLflow AI Gateway versions 3.13.0 through 3.15.2 contain a server-side request forgery (SSRF) vulnerability due to lack of validation on the api_base parameter when creating a gateway secret. Any authenticated user, including those with read-only access, can create a secret with a malicious api_base pointing to internal addresses. This allows the gateway proxy endpoint to issue HTTP requests to arbitrary internal resources, potentially exposing sensitive cloud instance metadata and IAM credentials. The vulnerability arises because the existing SSRF protections are not applied to this code path, and the CreateGatewaySecret action lacks specific permission scope enforcement.