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.
http://www.vupen.com/english/advisories/2009/3224
http://secunia.com/advisories/37321
http://msmtp.sourceforge.net/news.html
http://lists.opensuse.org/opensuse-security-announce/2010-01/msg00007.html