CVE-2026-55864

GeoNetwork's SLD tooling endpoint (POST /api/tools/ogc/sld) performs a server-side HTTP GET to a caller-supplied WMS server URL without any validation, allowing unauthenticated server-side request forgery (CWE-918). Any anonymous attacker can make the GeoNetwork server issue arbitrary outbound HTTP requests to internal hosts, and because the fetched body is stored and downloadable when it is XML, the SSRF is non-blind and responses can be read back. This enables internal data disclosure, authentication or authorization bypass on internal services, and reconnaissance of the server's private network. All GeoNetwork deployments running releases before the patched versions 4.4.12 and 4.2.17 are affected, including internet-exposed public catalog instances. No public proof-of-concept or confirmed in-the-wild exploitation is known, and the issue is not listed in CISA KEV.

What to do: Upgrade GeoNetwork to 4.4.12 or 4.2.17 (per the 4.4.x/4.2.x branch in use), referencing the upstream fix in pull request #9343. As interim mitigation, restrict unauthenticated access to /api/tools/ogc/sld at a reverse proxy and apply egress filtering from the GeoNetwork host to internal/loopback/cloud-metadata addresses; check logs for unexpected outbound requests issued by the SLD endpoint.