The IPv4 implementation on Cisco ASR 1000 devices with software 15.5(3)S allows remote attackers to cause a denial of service (ESP QFP CPU consumption) by triggering packet fragmentation and reassembly, aka Bug ID CSCuv71273.
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.