The Neighbor Discovery (ND) protocol implementation in the IPv6 stack in Cisco IOS 15.3(3)S0.1 on ASR devices mishandles internal tables, which allows remote attackers to cause a denial of service (memory consumption or device crash) via a flood of crafted ND messages, aka Bug ID CSCup28217.
Improper Restriction of Operations within the Bounds of a Memory Buffer The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.