A vulnerability in the Access Network Query Protocol (ANQP) ingress frame processing functionality of Cisco Wireless LAN Controllers could allow an unauthenticated, Layer 2 RF-adjacent attacker to cause an affected device to restart unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to incomplete input validation of ANQP query frames by the affected device. An attacker could exploit this vulnerability by sending a malformed ANQP query frame to an affected device that is on an RF-adjacent network. A successful exploit could allow the attacker to cause the affected device to restart unexpectedly, resulting in a DoS condition. This vulnerability affects Cisco Wireless LAN Controllers that are running a vulnerable release of Cisco WLC Software and are configured to support Hotspot 2.0. Cisco Bug IDs: CSCve05779.