How severe is CVE-2009-3766?

CVE-2009-3766 has a CVSS 2.0 base score of 6.8, rated medium severity.

Is CVE-2009-3766 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-3766?

CVE-2009-3766 affects Mutt. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2009-3766?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2009-3766 published?

CVE-2009-3766 was published on 2009-10-23 and last updated on 2026-06-16.

CVE-2009-3766

CVE-2009-3766 is a medium-severity vulnerability in Mutt 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. The underlying weakness is classified as CWE-310.

Key facts

Severity: Medium (CVSS 2.0 base score 6.8)
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-310
Affected product: Mutt
Published: 2009-10-23
Last modified: 2026-06-16

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.

Frequently asked questions

What is 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.
How severe is CVE-2009-3766?: CVE-2009-3766 has a CVSS 2.0 base score of 6.8, rated medium severity.
Is CVE-2009-3766 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-3766?: CVE-2009-3766 affects Mutt. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2009-3766?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2009-3766 published?: CVE-2009-3766 was published on 2009-10-23 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:a:mutt:mutt:*:*:*:*:*:*:*:*

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Threat intelligence

Threat-intel indicators referencing this CVE:

181.143.162.230 (ipv4-addr)
61.19.69.203 (ipv4-addr)
50.255.62.89 (ipv4-addr)
218.4.91.163 (ipv4-addr)
45.84.120.3 (ipv4-addr)
45.232.73.84 (ipv4-addr)
223.197.186.7 (ipv4-addr)
218.51.148.194 (ipv4-addr)