CVE-2011-1431: Frederik Vermeulen Netqmail

Medium severity, CVSS 6.8. EPSS: 4.6% chance of exploitation in the next 30 days.

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.

Affected products

• Frederik Vermeulen Netqmail: version 1.06 only

Published 2011-03-16. Last modified 2026-06-16.