CVE-2009-3765: Mutt

Medium severity, CVSS 6.8. EPSS: 1.1% chance of exploitation in the next 30 days.

mutt_ssl.c in mutt 1.5.19 and 1.5.20, when OpenSSL is used, does not properly handle a '\0' character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

Affected products

• Mutt Mutt: version 1.5.19 only; version 1.5.20 only

Published 2009-10-23. Last modified 2026-06-16.