The IPv6 snooping functionality in the first-hop security subsystem in Cisco IOS 12.2, 15.0, 15.1, 15.2, 15.3, 15.4, and 15.5 and IOS XE 3.2SE, 3.3SE, 3.3XO, 3.4SG, 3.5E, and 3.6E before 3.6.3E; 3.7E before 3.7.2E; 3.9S and 3.10S before 3.10.6S; 3.11S before 3.11.4S; 3.12S and 3.13S before 3.13.3S; and 3.14S before 3.14.2S allows remote attackers to cause a denial of service (device reload) via a malformed ND packet with the Cryptographically Generated Address (CGA) option, aka Bug ID CSCuo04400.