Uplay PC is a desktop client which replaces individual game launchers previously used for Ubisoft games. With Uplay PC, you have all your Uplay enabled games and Uplay services in the same place and you get access to a whole new set of features for your PC games.
Uplay for PC suffers from an elevation of privileges vulnerability which can be used by a simple user that can change the executable file with a binary of choice. The vulnerability exist due to the improper permissions, with the 'F' flag (Full) for 'Users' group, making the entire directory 'Ubisoft Game Launcher' and its files and sub-dirs world-writable.