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 that will execute in the context of another administrator's browser when viewed in the REST Resources API. Access to the REST Resources API is limited to full administrators by default and granting non-administrators access to this endpoint should be carefully considered as it may allow access to files containing sensitive information. Versions 2.23.3 and 2.24.0 contain a patch for this issue.