@Mail 3.64 for Windows allows remote attackers to cause a denial of service ("unusable" server) via a large number of POP3 connections to the server.
https://exchange.xforce.ibmcloud.com/vulnerabilities/15320
http://www.securityfocus.com/bid/9749
http://secunia.com/advisories/10978
http://members.lycos.co.uk/r34ct/main/%40mail_3.64/%40mail_3.64.txt