A vulnerability in the web-based GUI of Cisco IP Phone 6800, 7800, and 8800 Series with Multiplatform Firmware could allow an authenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the web-based interface of an affected system. The vulnerability is due to insufficient validation of user-supplied input by the web-based GUI of an affected system. An attacker could exploit this vulnerability by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.