Cisco IOS before 15.1(1)SY on ASR 1000 devices, when Multicast Listener Discovery (MLD) tracking is enabled for IPv6, allows remote attackers to cause a denial of service (device reload) via crafted MLD packets, aka Bug ID CSCtz28544.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.