The ALG module in Cisco IOS 15.0 through 15.4 does not properly implement SIP over NAT, which allows remote attackers to cause a denial of service (device reload) via multipart SDP IPv4 traffic, aka Bug ID CSCun54071.
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.