The locally served web site on the Garmin WDU (v1 1.4.6 and v2 5.0) allows a reflected cross site scripting (XSS) attack. This allows an attacker on the local network segment to execute arbitrary JavaScript code within the context of the WDU webpage. Full administrator level access to the device is possible. To initiate an exploit of this vulnerability, the victim must execute two actions: (1) view a specific URL served by the WDU, and (2) click an element on the rendered page.