dot11t/t_if_dot11_hal_ath.c in Cisco IOS 12.3, 12.4, 15.0, and 15.1 allows remote attackers to cause a denial of service (assertion failure and reboot) via 802.11 wireless traffic, as demonstrated by a video call from Apple iOS 5.0 on an iPhone 4S, aka Bug ID CSCtt94391.