Hastymail 1.5 and earlier before 20061008 allows remote authenticated users to send arbitrary SMTP commands by placing them after a CRLF.CRLF sequence in the smtp_message parameter. NOTE: this crosses privilege boundaries if the SMTP server configuration prevents a user from establishing a direct SMTP session. NOTE: this is a different type of issue than CVE-2006-5262.
https://exchange.xforce.ibmcloud.com/vulnerabilities/29407
http://www.vupen.com/english/advisories/2006/3956
http://www.securityfocus.com/bid/20424
http://www.securityfocus.com/archive/1/453417/100/0/threaded