CVE-2009-3766

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.

Published: 2009-10-23 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2009-3766 is rated Moderate Risk (49.6/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.14%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2009-3766

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.52% 1.14% +0.62%
2 2026-06-06 0.40% 0.52% +0.12%
3 2026-04-12 — 0.40% —

Full EPSS history (18 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2009-3766

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2009-3766

OS Trackers for CVE-2009-3766

vendor priority summary link
debian unimportant CVE-2009-3766 unimportant priority: Debian including 1 source packages (mutt), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2009-3766
redhat medium — https://access.redhat.com/security/cve/CVE-2009-3766
ubuntu negligible CVE-2009-3766 negligible priority: Ubuntu including 1 source packages (mutt), 7 status rows across 7 suites (dapper, hardy, intrepid, jaunty, karmic, lucid, upstream): ignored 6, needs-triage 1. https://ubuntu.com/security/CVE-2009-3766

Vendor comments (NVD) for CVE-2009-3766

  • Red Hat (2009-11-26T00:00:00)

    Red Hat is aware of this issue and is tracking it via the following bug: https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=CVE-2009-3766 The Red Hat Security Response Team has rated this issue as having moderate security impact, a future update may address this flaw.

Affected software / configurations for CVE-2009-3766

Vendor Product Version Raw CPE
mutt mutt >= 1.5.16, < 1.5.19 cpe:2.3:a:mutt:mutt:*:*:*:*:*:*:*:*

References for CVE-2009-3766

URL Tags
http://dev.mutt.org/trac/ticket/3087 Patch Vendor Advisory
http://marc.info/?l=oss-security&m=125198917018936&w=2 Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2009/10/26/1 Mailing List Third Party Advisory
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