GeoServer is an open source software server written in Java that allows users to share and edit geospatial data. A stored cross-site scripting (XSS) vulnerability exists in versions prior to 2.23.3 and 2.24.0 that enables an authenticated administrator with workspace-level privileges to store a JavaScript payload in uploaded style/legend resources or in a specially crafted datastore file that will execute in the context of another user's browser when viewed in the Style Publisher. Access to the Style Publisher is available to all users although data security may limit users' ability to trigger the XSS. Versions 2.23.3 and 2.24.0 contain a fix for this issue.
https://osgeo-org.atlassian.net/browse/GEOS-11155
https://osgeo-org.atlassian.net/browse/GEOS-11149
https://github.com/geoserver/geoserver/security/advisories/GHSA-9rfr-pf2x-g4xf