How severe is CVE-2026-55864?

No CVSS score has been assigned to CVE-2026-55864 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-55864?

CVE-2026-55864 affects the following packages: org.geonetwork-opensource:gn-web-app (Maven), org.geonetwork-opensource:gn-web-app (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-55864?

Update org.geonetwork-opensource:gn-web-app to 4.4.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55864 is resolved across your whole dependency graph.

How do I detect CVE-2026-55864 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.geonetwork-opensource:gn-web-app. 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.

How do I mitigate CVE-2026-55864 if there is no patch (or I can't update yet)?

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 does O3 Security protect against CVE-2026-55864?

O3 pinpoints whether CVE-2026-55864 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-55864 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-55864 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was CVE-2026-55864 published, and has it been updated?

CVE-2026-55864 was published on September 9, 2026 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

Not in CISA KEV

CVE-2026-55864

Fix: geonetwork/core-geonetwork#9343

CVE-2026-55864 is a security vulnerability in org.geonetwork-opensource:gn-web-app. O3 Security confirms whether CVE-2026-55864 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

GeoNetwork Web Module: Unauthenticaded Server-Side Request Forgery in SLD Tool

Published

Sep 9, 2026

Updated

Sep 10, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Sep 10, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

2 pkgs affected

☕org.geonetwork-opensource:gn-web-app☕org.geonetwork-opensource:gn-web-app

Real-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

An unauthenticated server-side request forgery vulnerability lets any anonymous user make the GeoNetwork server issue arbitrary outbound HTTP requests. This gives an external attacker a position inside the server's network, making it possible to make internal requests no matter if the response is XML-type or not.

The SLD tooling endpoint POST /api/tools/ogc/sld takes a caller-supplied WMS server URL and performs a server-side HTTP GET to it, with no validation. The fetched body can also be stored and downloaded if the output of the outbound request is in XML format, making the SSRF non-blind.

Impact

Any unauthenticated user can make the server send arbitrary HTTP requests to internal hosts it would never expose publicly, and read the responses back if the request responses are XML. This enables internal data disclosure, for example, configuration files that return as XML, authorization bypass, and reconnaissance of the internal network all from an anonymous position.

Resolution

Patched releases:

4.4.12
4.2.17

Resources

https://github.com/geonetwork/core-geonetwork/pull/9343

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.geonetwork-opensource:gn-web-app`	≥ 4.4.0&&< 4.4.12	4.4.12
☕Maven	`org.geonetwork-opensource:gn-web-app`	≥ 4.0.0&&< 4.2.17	4.2.17

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.geonetwork-opensource:gn-web-app. 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.geonetwork-opensource:gn-web-app to 4.4.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55864 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-2026-55864 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-2026-55864. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary An unauthenticated server-side request forgery vulnerability lets any anonymous user make the GeoNetwork server issue arbitrary outbound HTTP requests. This gives an external attacker a position inside the server's network, making it possible to make internal requests no matter if the response is XML-type or not. The SLD tooling endpoint `POST /api/tools/ogc/sld` takes a caller-supplied **WMS server URL** and performs a **server-side HTTP GET** to it, with no validation. The fetched body can also be stored and downloaded if the output of the outbound request is in XML format, maki

O3 Security · Impact-Aware SCA

Is CVE-2026-55864 in your dependencies?

O3 detects CVE-2026-55864 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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