CVE-2009-3639 Security feature bypass in n/a

What is CVE-2009-3639?

CVE-2009-3639 is a medium-severity vulnerability in n/a, published on 28 Oct 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-310

Which versions are affected by CVE-2009-3639?

It affects 1 product.

Products include Proftpd Proftpd.

How do I fix CVE-2009-3639?

Upgrade to a fixed version.

Is CVE-2009-3639 being exploited?

There is no known exploitation of CVE-2009-3639 in the wild and no public exploit code.

Other vulnerabilities in n/a

• CVE-2010-4221 Memory corruption in n/a Critical 10.0
• CVE-2010-20103 ProFTPD 1.3.3c Backdoor Command Execution Critical 9.3
• CVE-2011-4130 Use after free in n/a Critical 9.0
• CVE-2026-63090 ProFTPD mod_sftp Heap Buffer Overflow via SFTP Packet Reassembly High 8.7
• CVE-2026-35025 ProFTPD ACL Bypass via /proc/self/root Path Prefix in RNFR High 8.6

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2009-3639, DSA-1925-1, GHSA-4vq9-9g4j-pgg4.