CVE-2009-3639

Severity: medium (CVSS 5.8 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 5.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2009-10-28 · updated 2026-06-16
Weakness: CWE-310

Description

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.

Affected products

ProFTPD: through 1.3.2; 1.3.1, 1.3.2, 1.3.2-rc1, 1.3.2-rc2, 1.3.2-rc4, 1.3.3-rc1

References

http://bugs.proftpd.org/show_bug.cgi?id=3275
http://marc.info/?l=oss-security&m=125630966510672&w=2
http://marc.info/?l=oss-security&m=125632960508211&w=2
http://secunia.com/advisories/37131
http://secunia.com/advisories/37219
http://www.debian.org/security/2009/dsa-1925
http://www.mandriva.com/security/advisories?name=MDVSA-2009:288
http://www.securityfocus.com/bid/36804
https://bugzilla.redhat.com/show_bug.cgi?id=530719
https://exchange.xforce.ibmcloud.com/vulnerabilities/53936
https://www.redhat.com/archives/fedora-package-announce/2009-November/msg00642.html
https://www.redhat.com/archives/fedora-package-announce/2009-November/msg00649.html

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