The SMTP service of MailEnable Standard 1.92 and earlier, Professional 2.0 and earlier, and Enterprise 2.0 and earlier before the MESMTPC hotfix, allows remote attackers to cause a denial of service (application crash) via a HELO command with a null byte in the argument, possibly triggering a length inconsistency or a missing argument.
https://exchange.xforce.ibmcloud.com/vulnerabilities/27387
http://www.vupen.com/english/advisories/2006/2520
http://www.securityfocus.com/bid/18630
http://www.securityfocus.com/archive/1/438374/100/0/threaded
http://www.mailenable.com/hotfix/mesmtpc.zip
http://www.divisionbyzero.be/?p=174
http://www.divisionbyzero.be/?p=173