A GeoServer that uses ENTITY_RESOLUTION_ALLOWLIST may allow attacker to perform unauthenticated Server-Side Request Forgery (SSRF).
Details
This vulnerability requires that GeoServer is set up to use a proxy base URL and the ENTITY_RESOLUTION_ALLOWLIST (default since 2.25.0):
Impact
This vulnerability allows an attacker to cause GeoServer to make requests to an unintended location.
Workaround
GeoServer installations are only affected by this vulnerability if they use a proxy base URL that does not contain a URL path or end with a slash (e.g., https://somesite.org instead of https://somesite.org/ or https://somesite.org/geoserver). If the proxy base URL does not contain a path, adding a slash to the end of the URL will mitigate this vulnerability.