A stored DOM Cross-Site Scripting vulnerability (CWE-79) in the AVideo YPTSocket plugin lets any unauthenticated remote attacker execute arbitrary JavaScript in the authenticated origin of every administrator currently viewing a page that renders the YPTSocket online-users debug panel. plugin/YPTSocket/getWebSocket.json.php issues a signed WebSocket token to any anonymous caller, and MessageSQLiteV2::onOpen at plugin/YPTSocket/MessageSQLiteV2.php lines 91 and 110 reads the attacker-controlled webSocketSelfURI and page_title query parameters from the WebSocket connection URL with no validation. Both values persist into the in-memory SQLite connections table and broadcast inside the users_id_online array sent to every connected client; on the client, plugin/YPTSocket/script.js::updateSocketUserCard interpolates the broadcast page_title into an HTML template literal that is passed to jQuery $.append(html), which parses attacker bytes into live DOM nodes including <img> with inline event handlers.