Buffer overflow in MailCarrier 2.51 allows remote attackers to execute arbitrary code via a long (1) EHLO and possibly (2) HELO command.
https://exchange.xforce.ibmcloud.com/vulnerabilities/17861
https://euvd.enisa.europa.eu/vulnerability/EUVD-2004-1632
http://www.securityfocus.com/bid/11535