How severe is CVE-2009-3765?

CVE-2009-3765 has a CVSS 2.0 base score of 6.8, rated medium severity.

Is CVE-2009-3765 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-3765?

CVE-2009-3765 primarily affects Mutt. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-3765?

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

When was CVE-2009-3765 published?

CVE-2009-3765 was published on 2009-10-23 and last updated on 2026-06-16.

CVE-2009-3765

CVE-2009-3765 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% (61st 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 1.5.19 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.

Frequently asked questions

What is CVE-2009-3765?: 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.
How severe is CVE-2009-3765?: CVE-2009-3765 has a CVSS 2.0 base score of 6.8, rated medium severity.
Is CVE-2009-3765 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-3765?: CVE-2009-3765 primarily affects Mutt. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-3765?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2009-3765 published?: CVE-2009-3765 was published on 2009-10-23 and last updated on 2026-06-16.

References

Affected products (2)

cpe:2.3:a:mutt:mutt:1.5.19:*:*:*:*:*:*:*
cpe:2.3:a:mutt:mutt:1.5.20:*:*:*:*:*:*:*

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CVE-2013-0137 — Critical (CVSS 10.0): The default configuration of the Digital Alert Systems DASDEC EAS device before 2.0-2 and the Monroe Electronics R189…
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Browse all CWE-310 (Cryptographic Issues) vulnerabilities →

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)