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Fencer Vulns
medium 5.8

CVE-2009-3639 json

The mod_tls module in ProFTPD before 1.3.2b, and 1.3.3 before 1.3.3rc2, when the dNSNameRequired TLS option is enabled, does not properly h…

published 2009-10-28 17 y ago modified 2026-06-16 4 mo ago also EUVD-2009-3614

cvss
5.8
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
5.7%
EPSS 5.7% chance of exploitation in 30 days, percentile 93%
public exploits
0
none known

Summary

The mod_tls module in ProFTPD before 1.3.2b, and 1.3.3 before 1.3.3rc2, when the dNSNameRequired TLS option is enabled, does not properly handle a '\0' character in a domain name in the Subject Alternative Name field of an X.509 client certificate, which allows remote attackers to bypass intended client-hostname restrictions via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

Patch / fix

  • proftpd-dfsg Debian 14, Debian 13, Debian 12 1.3.2a-2

debian advisories DEBIAN-CVE-2009-3639

  • proftpd openSUSE Tumbleweed 1.3.5b-2.5

opensuse advisories openSUSE-SU-2024:10048-1

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-2009-3639 updated cvss 4.3

ProFTPD: Doesn't properly handle NULL character in subjectAltName

  • 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

5.70% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 2.0 5.8 AV:N/AC:M/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.