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Fencer Vulns
medium 6.4

CVE-2009-3942 json

Martin Lambers msmtp before 1.4.19, when OpenSSL is used, does not properly handle a '\0' character in a domain name in the (1) subject's C…

published 2009-11-16 16 y ago modified 2026-06-16 4 mo ago also EUVD-2009-3913

cvss
6.4
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 65%
public exploits
0
none known

Summary

Martin Lambers msmtp before 1.4.19, when OpenSSL is used, does not properly handle a '\0' character in a domain name in the (1) subject's Common Name or (2) Subject Alternative Name 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.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2009-3942 updated

msmtp SSL NULL prefix flaw

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.08% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:N/I:P/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.