Cisco 4100 and 4400, Airespace 4000, and Catalyst 6500 and 3750 Wireless LAN Controller (WLC) software before 3.2 20070727, 4.0 before 20070727, and 4.1 before 4.1.180.0 allows remote attackers to cause a denial of service (traffic amplification or ARP storm) via a crafted unicast ARP request that (1) has a destination MAC address unknown to the Layer-2 infrastructure, aka CSCsj69233; or (2) occurs during Layer-3 roaming across IP subnets, aka CSCsj70841.