vulnerability / NVI-00015307 / Revision 1
GeoServer has a Server-Side Template Injection (SSTI) vulnerability in processing FreeMarker templates
GitHub lists this reviewed advisory for org.geoserver:gs-main, org.geoserver:gs-wms, org.geoserver.web:gs-web-app. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
7.2 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
org.geoserver:gs-main
source listed< 2.27.0
### Summary A server-side template injection (SSTI) vulnerability exist that allows an authenticated administrator to upload FreeMarker templates containing malicious content that can execute OS commands and read from or write to arbitrary files on the server. These FreeMarker templates are used in a plain GeoServer instance (no extension or community modules) for WMS GetFeatureInfo HTML and JSON and WMS GetMap KML and GeoRSS output formats. ### Details The org.geoserver.template.TemplateUtils.getSafeConfiguration() method attempts to block access to the class freemarker.template.utility.Execute but it is still possible to gain access to it and other sensitive functionality by chaining a specific sequence of method calls. ### Impact This vulnerability can lead to executing arbitrary code and reading and writing arbitrary files. ### Resolution GeoServer 2.27.0 addresses this vulnerability with several new application properties: * ``GEOSERVER_FREEMARKER_BLOCK_LIST`` * ``GEOSERVER_FREEMARKER_ALLOW_LIST`` * ``GEOSERVER_FREEMARKER_API_EXPOSED`` These application properties default to restricting the objects template authors can access, and limit access to "getter" methods used to
org.geoserver:gs-wms
source listed< 2.27.0
### Summary A server-side template injection (SSTI) vulnerability exist that allows an authenticated administrator to upload FreeMarker templates containing malicious content that can execute OS commands and read from or write to arbitrary files on the server. These FreeMarker templates are used in a plain GeoServer instance (no extension or community modules) for WMS GetFeatureInfo HTML and JSON and WMS GetMap KML and GeoRSS output formats. ### Details The org.geoserver.template.TemplateUtils.getSafeConfiguration() method attempts to block access to the class freemarker.template.utility.Execute but it is still possible to gain access to it and other sensitive functionality by chaining a specific sequence of method calls. ### Impact This vulnerability can lead to executing arbitrary code and reading and writing arbitrary files. ### Resolution GeoServer 2.27.0 addresses this vulnerability with several new application properties: * ``GEOSERVER_FREEMARKER_BLOCK_LIST`` * ``GEOSERVER_FREEMARKER_ALLOW_LIST`` * ``GEOSERVER_FREEMARKER_API_EXPOSED`` These application properties default to restricting the objects template authors can access, and limit access to "getter" methods used to
org.geoserver.web:gs-web-app
source listed< 2.27.0
### Summary A server-side template injection (SSTI) vulnerability exist that allows an authenticated administrator to upload FreeMarker templates containing malicious content that can execute OS commands and read from or write to arbitrary files on the server. These FreeMarker templates are used in a plain GeoServer instance (no extension or community modules) for WMS GetFeatureInfo HTML and JSON and WMS GetMap KML and GeoRSS output formats. ### Details The org.geoserver.template.TemplateUtils.getSafeConfiguration() method attempts to block access to the class freemarker.template.utility.Execute but it is still possible to gain access to it and other sensitive functionality by chaining a specific sequence of method calls. ### Impact This vulnerability can lead to executing arbitrary code and reading and writing arbitrary files. ### Resolution GeoServer 2.27.0 addresses this vulnerability with several new application properties: * ``GEOSERVER_FREEMARKER_BLOCK_LIST`` * ``GEOSERVER_FREEMARKER_ALLOW_LIST`` * ``GEOSERVER_FREEMARKER_API_EXPOSED`` These application properties default to restricting the objects template authors can access, and limit access to "getter" methods used to
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-wf6j-gr27-g7ch ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.