Buffer overflow in IPSwitch IMail SMTP server 6.06 and possibly prior versions allows remote attackers to execute arbitrary code via a long From: header.
https://exchange.xforce.ibmcloud.com/vulnerabilities/6445
https://euvd.enisa.europa.eu/vulnerability/EUVD-2001-0490
http://ipswitch.com/Support/IMail/news.html
http://archives.neohapsis.com/archives/bugtraq/2001-04/0433.html