istream.c in w3m 0.5.2 and possibly other versions, when ssl_verify_server is enabled, 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/2010/1928
http://www.vupen.com/english/advisories/2010/1879
http://www.vupen.com/english/advisories/2010/1467
http://www.securitytracker.com/id?1024252
http://www.securityfocus.com/bid/40837
http://www.redhat.com/support/errata/RHSA-2010-0565.html
http://www.openwall.com/lists/oss-security/2010/06/14/4
http://secunia.com/advisories/40733
http://secunia.com/advisories/40134
http://lists.opensuse.org/opensuse-security-announce/2010-08/msg00001.html
http://lists.fedoraproject.org/pipermail/package-announce/2010-July/044401.html