CVE-2009-3766

Severity: medium (CVSS 6.8 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2009-10-23 · updated 2026-06-16
Weakness: CWE-310

Description

mutt_ssl.c in mutt 1.5.16 and other versions before 1.5.19, when OpenSSL is used, does not verify the domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.

Affected products

mutt: from 1.5.16 before 1.5.19 — fixed in 1.5.19

How to fix

Upgrade to a fixed version: mutt 1.5.19. Check the vendor advisory for mitigations.

References

http://dev.mutt.org/trac/ticket/3087
http://marc.info/?l=oss-security&m=125198917018936&w=2
http://www.openwall.com/lists/oss-security/2009/10/26/1
http://dev.mutt.org/trac/ticket/3087
http://marc.info/?l=oss-security&m=125198917018936&w=2
http://www.openwall.com/lists/oss-security/2009/10/26/1

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