CVE-2009-4565
CWE-310Published: January 4, 2010· Updated: Jun 16, 2026
Official Description
sendmail before 8.14.4 does not properly handle a '\0' character in a Common Name (CN) field of an X.509 certificate, which (1) allows man-in-the-middle attackers to spoof arbitrary SSL-based SMTP servers via a crafted server certificate issued by a legitimate Certification Authority, and (2) allows remote attackers to bypass intended access restrictions via a crafted client certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.
Technical Analysis
CVE-2009-4565 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (40)
Quick Facts
Related CVEs (CWE-310)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2009-4565 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts