GeoNode versions 4.0 before 4.4.5 and 5.0 before 5.0.2 contain a server-side request forgery vulnerability in the service registration endpoint that allows authenticated attackers to trigger outbound network requests to arbitrary URLs by submitting a crafted service URL during form validation. Attackers can probe internal network targets including loopback addresses, RFC1918 private IP ranges, link-local addresses, and cloud metadata services by exploiting insufficient URL validation in the WMS service handler without private IP filtering or allowlist enforcement.