GeoNetwork is a catalog application to manage spatially referenced resources. Prior to 4.2.17 and 4.4.12, POST /api/tools/ogc/sld accepted a caller-supplied WMS server URL and performed a server-side HTTP GET without destination validation. An anonymous attacker could make the GeoNetwork server send requests to internal hosts that are not publicly reachable. When the outbound response was XML, the endpoint could store and return the fetched body, making the request forgery non-blind and enabling internal data disclosure, authorization bypass, and network reconnaissance. This issue is fixed in versions 4.2.17 and 4.4.12.