As first reported on The Round Table by Storm-giant, an article in Rock, Paper, Shotgun deals with a genuine threat to Uplay users' computer systems.

"... as described here, with the right piece of code any website can call up a Uplay window and from that might be able to slip a program install or launch of their choice onto your PC. (...) With news of this backdoor spreading like wildfire and proof of concept code already out there, there's a very real chance that someone will try to achieve something unpleasant with it before Ubisoft can shut it down.

The fault does appear to specifically lie with a browser plugin Uplay installs rather than Uplay itself, so remove that from your Firefox/Chrome/IE/etc extensions..."

  • Firefox: Tools – Add-ons – Plugins – Disable the Uplay and Uplay PC Hub plugins.
  • Chrome: Visit about: plugins and disable.
    Opera: Settings – Preferences – Advanced – Downloads – Search "Uplay", delete.

Just FYI: Heroes VI is on the list of games known to be affected.