mapfish-print: XXE on MapFish Print allows reading arbitrary files of certain types

mapfish-print is a component of MapFish for printing templated cartographic maps. Prior to 3.28.30, 3.30.32, 3.31.24, 3.33.16, and 4.0.5, MapFish Print accepts an attacker-controlled GML layer url in requests to the /api/print3/print endpoint and fetches XML parsed by core/src/main/java/org/mapfish/print/map/geotools/GmlLayer.java without disabling external entities and external DTDs. A remote XML document and DTD can expand a local file entity, and the resulting content can be exposed through the GML parsing and error path. This allows unauthenticated attackers to read files such as operating-system account data, Kubernetes service-account tokens, and certificates. Replacing the file entity target with an internal HTTP endpoint also permits server-side request forgery. This issue is fixed in versions 3.28.30, 3.30.32, 3.31.24, 3.33.16, and 4.0.5.