GeoServer's MapML HTML Page vulnerable to Stored Cross-Site Scripting (XSS)
A stored cross-site scripting (XSS) vulnerability exists that enables an authenticated administrator with workspace-level privileges to store a JavaScript payload in the GeoServer catalog that will execute in the context of another user's browser when viewed in the MapML HTML Page. The MapML extension must be installed and access to the MapML HTML Page is available to all users although data security may limit users' ability to trigger the XSS.