The dissector_cvs function in dissectors/ec_cvs.c in Ettercap 0.8.1 allows remote attackers to cause a denial of service (out-of-bounds read) via a packet containing only a CVS_LOGIN signature.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.