source: http://www.securityfocus.com/bid/930/info

There is a denial of service condition in Nosque Workshop's MsgCore SMTP server. The problem lies in memory used to store server input not being deallocated and eventually exhausted, causing the target NT host to freeze requiring a reboot. If a smtp client (or user sending input manually) sends multiple sequences of "HELO/ MAIL FROM/ RCPT TO / DATA" in a single connection, the memory allocated to store all of those values will not be freed and the target will stop functioning once memory runs out. 

https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/bin-sploits/19725.zip