Buffer OVERFLOW

The Buffer OverFlow is a special case of violation of memory safety.
the normal program access the alocated memory which provide by the script of the program itself, but the attacer triggered the buffer OverFlow by input an excecution code that infected the running process.

the ressult is anomaly of the program's operation such : error on the accessing memory, incorect output result, a breach of system security, and etc..., those vulnerabilities could be exploited by th attacker.

http://en.wikipedia.org/wiki/Buffer_overflow