Advantech WISE-DeviceOn Server versions prior to 5.4 contain a stored cross-site scripting (XSS) vulnerability in the /rmm/v1/devicemap/plan endpoint. When an authenticated user adds an area to a map entry, the name parameter is stored and later rendered in the map list without HTML sanitization. An attacker can inject malicious script into the area name, which is then executed in the browser context of users who view or interact with the affected map entry, potentially enabling session compromise and unauthorized actions as the victim.