Buffer overflow in DynFX MailServer version 2.10 allows remote attackers to conduct a denial of service via a long username to the POP3 service.
https://exchange.xforce.ibmcloud.com/vulnerabilities/6615
http://www.securityfocus.com/bid/2781
http://archives.neohapsis.com/archives/bugtraq/2001-05/0278.html