CVE-2011-1431

CVE-2011-1431 is a medium-severity vulnerability in Frederik Vermeulen Netqmail with a CVSS 2.0 base score of 6.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

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.

Frequently asked questions

What is CVE-2011-1431?
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.
How severe is CVE-2011-1431?
CVE-2011-1431 has a CVSS 2.0 base score of 6.8, rated medium severity.
Is CVE-2011-1431 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-1431?
CVE-2011-1431 affects Frederik Vermeulen Netqmail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2011-1431?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2011-1431 published?
CVE-2011-1431 was published on 2011-03-16 and last updated on 2026-06-16.

References

Affected products (1)