Seems to have been patched already, so update Uplay and it should be ok:
Original OP content below:
The important bit of that post:
The original post for the hack:
Ubisoft installs a backdoor that allows any website to take over your computer. The Sony BMG rootkit was also DRM and required product recall when it was discovered.
Fixes before people start going crazy:
Originally Posted by SparkTR
You want to fix this? Disable the plug-in in your browser. Done. People talking about reformatting their PCs are making me facepalm.
Google chrome users: You can go to "about:plugins" and disable this and all other things that might expose you to extra security risks such as "Microsoft Office" (even "Native Client") or any other plugins that exposed in there by 3rd party without any confirmation.