Mozilla 1.9 M8 and earlier, Mozilla Firefox 2 before 2.0.0.15, SeaMonkey 1.1.5 and other versions before 1.1.10, Netscape 9.0, and other Mozilla-based web browsers, when a user accepts an SSL server certificate on the basis of the CN domain name in the DN field, regard the certificate as also accepted for all domain names in subjectAltName:dNSName fields, which makes it easier for remote attackers to trick a user into accepting an invalid certificate for a spoofed web site.

More... (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2008-2809)