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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

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

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

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.

What is the EPSS score for CVE-2026-55864?

CVE-2026-55864 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 47th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-55864?

CVE-2026-55864 is classified as Server-Side Request Forgery (SSRF) (CWE-918). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

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

CVE-2026-55864 was published on September 15, 2026 and was last updated on October 21, 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 — gn-web-app

Fix: geonetwork/core-geonetwork@17fdae2

CVE-2026-55864 is a Server-Side Request Forgery (SSRF) vulnerability in org.geonetwork-opensource:gn-web-app. A fix is available for org.geonetwork-opensource:gn-web-app — see the affected versions and patch details below.

GeoNetwork: Unauthenticaded Server-Side Request Forgery in SLD Tool

Also known asGHSA-5hx7-j24v-rffj

Published

Sep 15, 2026

Updated

Oct 21, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-55864.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs47th percentile — riskier than 47% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from 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`org.geonetwork-opensource:gn-web-app:4.4.12`
☕Maven	`org.geonetwork-opensource:gn-web-app`	≥ 4.0.0&&< 4.2.17	4.2.17`org.geonetwork-opensource:gn-web-app: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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

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