Unspecified vulnerability in the H.323 implementation in Cisco IOS 12.1 through 12.4 and 15.0 through 15.1, and IOS XE 2.5.x before 2.5.2 and 2.6.x before 2.6.1, allows remote attackers to cause a denial of service (device reload) via crafted H.323 packets, aka Bug ID CSCtc73759.