CVE-2023-41339
Unsecured WMS dynamic styling sld=<url> parameter affords blind unauthenticated SSRF in GeoServer
GeoServer is an open source software server written in Java that allows users to share and edit geospatial data. 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. This vulnerability can be used to steal user NetNTLMv2 hashes which could be relayed or cracked externally to gain further access. This vulnerability has been patched in versions 2.22.5 and 2.23.2.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Unsecured WMS dynamic styling sld=<url> parameter affords blind unauthenticated SSRF in GeoServer
GeoServer is an open source software server written in Java that allows users to share and edit geospatial data. 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. This vulnerability can be used to steal user NetNTLMv2 hashes which could be relayed or cracked externally to gain further access. This vulnerability has been patched in versions 2.22.5 and 2.23.2.
- Record
CVE-2023-41339- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L - Weakness
- CWE-918
- Updated
- 2026-11-02
EUVDEUVD-2023-2717
GeoServer is an open source software server written in Java that allows users to share and edit geospatial data. 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. This vulnerability can be used to steal user NetNTLMv2 hashes which could be relayed or cracked externally to gain further access. This vulnerability has been patched in versions 2.22.5 and 2.23.2.
- Record
EUVD-2023-2717- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-cqpc-x2c6-2gmf
Unsecured WMS dynamic styling sld=<url> parameter affords blind unauthenticated SSRF
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:
- Navigate to Services > WMS Settings page
- Locate Dynamic styling heading
- 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:
- Navigate to Security > URL Checks
- Enable URL Checks are enabled setting
- Check the user manual for examples of how to trust specific locations:
^https://styles\.server\.net/cartography/.*$ - 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
- Record
GHSA-cqpc-x2c6-2gmf- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
NVD
GeoServer is an open source software server written in Java that allows users to share and edit geospatial data. 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. This vulnerability can be used to steal user NetNTLMv2 hashes which could be relayed or cracked externally to gain further access. This vulnerability has been patched in versions 2.22.5 and 2.23.2.
- Record
CVE-2023-41339- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
OSV
Unsecured WMS dynamic styling sld=<url> parameter affords blind unauthenticated SSRF in GeoServer
GeoServer is an open source software server written in Java that allows users to share and edit geospatial data. 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. This vulnerability can be used to steal user NetNTLMv2 hashes which could be relayed or cracked externally to gain further access. This vulnerability has been patched in versions 2.22.5 and 2.23.2.
- Record
CVE-2023-41339- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L - Weakness
- CWE-918
- Updated
- 2026-11-02
OSVGHSA-cqpc-x2c6-2gmf
Unsecured WMS dynamic styling sld=<url> parameter affords blind unauthenticated SSRF
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:
- Navigate to Services > WMS Settings page
- Locate Dynamic styling heading
- 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:
- Navigate to Security > URL Checks
- Enable URL Checks are enabled setting
- Check the user manual for examples of how to trust specific locations:
^https://styles\.server\.net/cartography/.*$ - 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
- Record
GHSA-cqpc-x2c6-2gmf- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
org.geoserver:gs-wmsMaven |
before 2.22.5 | 2.22.5 |
org.geoserver:gs-wmsMaven |
2.23.0 up to 2.23.2 | 2.23.2 |
org.geoserver.web:gs-web-appMaven |
before 2.22.5 | 2.22.5 |
org.geoserver.web:gs-web-appMaven |
2.23.0 up to 2.23.2 | 2.23.2 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-41339 is a high vulnerability (CVSS 8.6) in Geoserver, published October 24, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.63%, the 50th percentile. Fixed in org.geoserver:gs-wms 2.22.5.
References
github.com/geoserver/geoserver/security/advisories/GHSA-cqpc-x2c6-2gmf
nvd.nist.gov/vuln/detail/CVE-2023-41339