source: http://www.securityfocus.com/bid/755/info
 
The Avirt Mail Server 3.3a and 3.5 packages are vulnerable to a remote buffer overflow vulnerability. The buffer overflow can be initiated by passing 856 characters in the password field.

https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/bin-sploits/19580.zip