Reposting from a article on Rock, Paper, Shotgun. The fix is relatively simple (uninstall UPlay and the UPlay browser plugin), and the danger has been verified.
Incomplete list of games affected below:
Assassin’s Creed II
Assassin’s Creed: Brotherhood
Assassin’s Creed: Project Legacy
Assassin’s Creed Revelations
Assassin’s Creed III
Beowulf: The Game
Brothers in Arms: Furious 4
Call of Juarez: The Cartel
Driver: San Francisco
Heroes of Might and Magic VI
Just Dance 3
Prince of Persia: The Forgotten Sands
Pure Football
R.U.S.E.
Shaun White Skateboarding
Silent Hunter 5: Battle of the Atlantic
The Settlers 7: Paths to a Kingdom
Tom Clancy’s H.A.W.X. 2
Tom Clancy’s Ghost Recon: Future Soldier
Tom Clancy’s Splinter Cell: Conviction
Your Shape: Fitness Evolved
Not a complete list, and apparently there are a number that quietly install Uplay without user knowledge or consent. Given that the exploit is in the wild this is a very real threat.