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HIGH severity

CVE-2023-41339 — gs-wms

HIGH

CVE-2023-41339 is a high-severity (CVSS 8.6) Server-Side Request Forgery (SSRF) vulnerability in org.geoserver:gs-wms. A fix is available for org.geoserver:gs-wms — see the affected versions and patch details below.

Unsecured WMS dynamic styling sld=<url> parameter affords blind unauthenticated SSRF in GeoServer

Also known asGHSA-cqpc-x2c6-2gmf
Published
Updated
Affected
4 pkgs
Patched
4 / 4
Exploits
None indexed
Exploitation data as of Nov 4, 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-2023-41339.

EPSS Exploitation Probability

via FIRST.org ↗
0.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs50th percentile — riskier than 50% of all scored CVEsHighest risk
0.00%0.38%0.75%1.13%0.2%0.6%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

4 pkgs affected
☕org.geoserver:gs-wms☕org.geoserver:gs-wms☕org.geoserver.web:gs-web-app☕org.geoserver.web:gs-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

The WMS specification defines an sld=<url> parameter for GetMap, GetLegendGraphic and GetFeatureInfo operations for user supplied "dynamic styling". Enabling the use of dynamic styles, without also configuring URL checks, provides the opportunity for Service Side Request Forgery.

It is possible to use this for "Blind SSRF" on the WMS endpoint to steal NetNTLMv2 hashes via file requests to malicious servers.

Details

This vulnerability requires:

  • WMS Settings dynamic styling being enabled
  • Security URL checks to be disabled, or to be enabled and allowing file:\\* access

Impact

This vulnerability can be used to steal user NetNTLMv2 hashes which could be relayed or cracked externally to gain further access.

Mitigation

The ability to reference an external URL location is defined by the WMS standard GetMap, GetFeatureInfo and GetLegendGraphic operations. These operations are defined by an Industry and International standard and cannot be redefined by the GeoServer application in isolation.

To disable dynamic styling on GeoServer 2.10.3 and GeoServer 2.11.1:

  1. Navigate to Services > WMS Settings page
  2. Locate Dynamic styling heading
  3. Select the Disable usage of SLD and SLD_BODY parameters in GET requests and user styles in POST checkbox.

Resolution

To allow dynamic styling safely on GeoServer 2.22.5 and GeoServer 2.23.2:

  1. Navigate to Security > URL Checks
  2. Enable URL Checks are enabled setting
  3. Check the user manual for examples of how to trust specific locations: ^https://styles\.server\.net/cartography/.*$
  4. Enable dynamic styling on the Services > WMS Settings page, deselect the Disable usage of SLD and SLD_BODY parameters in GET requests and user styles in POST checkbox.

Use of dynamic styling safely is on by default in GeoServer 2.24.0.

References

Affected Packages

4 total 4 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.geoserver:gs-wmsall versions2.22.5org.geoserver:gs-wms:2.22.5
☕Mavenorg.geoserver:gs-wms≥ 2.23.0&&< 2.23.22.23.2org.geoserver:gs-wms:2.23.2
☕Mavenorg.geoserver.web:gs-web-appall versions2.22.5org.geoserver.web:gs-web-app:2.22.5
☕Mavenorg.geoserver.web:gs-web-app≥ 2.23.0&&< 2.23.22.23.2org.geoserver.web:gs-web-app:2.23.2

Affected Products

1 product · 2 configurations
Application
geoserverosgeo
≥ 2.23.0 && < 2.23.2
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.geoserver:gs-wms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.geoserver:gs-wms to 2.22.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-41339 is resolved across your whole dependency graph.

  3. 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 The WMS specification defines an ``sld=<url>`` parameter for GetMap, GetLegendGraphic and GetFeatureInfo operations for user supplied "dynamic styling". Enabling the use of dynamic styles, without also configuring URL checks, provides the opportunity for Service Side Request Forgery. It is possible to use this for "Blind SSRF" on the WMS endpoint to steal NetNTLMv2 hashes via file requests to malicious servers. ### Details This vulnerability requires: * WMS Settings dynamic styling being enabled * Security URL checks to be disabled, or to be enabled and allowing ``file:\\*``
O3 Security · Impact-Aware SCA

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CVE-2023-41339: gs-wms SSRF — Fixed in 2.22.5