Blizzard wanted everyone to be aware of this security warning...
Please be aware that a recently announced Microsoft Windows vulnerability was identified that if exploited could allow the execution of malicious code to affect a user’s machine by simply clicking on a web link. Players are urged to exercise caution when clicking on web links. It’s also important to note that even with all of the latest security updates, your system could still be vulnerable to this particular exploit until such a time when a patch is released.
For additional information, please visit this page.
http://www.microsoft.com/technet/securi ... 35423.mspx