A couple of days ago, Microsoft released a security advisory regarding animated cursors. In the report, they indicated that they are "investigating new public reports of attacks exploiting a vulnerability in the way Microsoft Windows handles animated cursor (.ani) files."

In answer to that, Blizzard poster Eyonix gave the following security advisory over at the World of Warcraft Forums:

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.