qmail-verify as used in netqmail 1.06 is prone to an information disclosure vulnerability. A local attacker can test for the existence of files and directories anywhere in the filesystem because qmail-verify runs as root and tests for the existence of files in the attacker's home directory, without dropping its privileges first.

qmail-verify as used in netqmail 1.06 is prone to a mail-address verification bypass vulnerability.

The STARTTLS implementation in qmail-smtpd.c in qmail-smtpd in the netqmail-1.06-tls patch for netqmail 1.06 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.