Multiple buffer overflows in Ipswitch IMail before 2006.21 allow remote attackers or authenticated users to execute arbitrary code via (1) the authentication feature in IMailsec.dll, which triggers heap corruption in the IMail Server, or (2) a long SUBSCRIBE IMAP command, which triggers a stack-based buffer overflow in the IMAP Daemon.

The STARTTLS implementation in the server in Ipswitch IMail 11.03 and earlier does not properly restrict I/O buffering, which allows man-in-the-middle attackers to insert commands into encrypted SMTP sessions by sending a cleartext command that is processed after TLS is in place, related to a "plaintext command injection" attack, a similar issue to CVE-2011-0411.