When he launched Diablo III, University of Toronto student Evan Andersen was shocked to see a screenshot from a pornographic website appear instead of the game's black loading screen.
Evan quickly noticed that the screenshot was taken from a Chrome incognito session he finished several hours before. Evan was able to identify the reason and explain it on his blog.
"So how did this happen? A bug in Nvidia’s GPU drivers. GPU memory is not erased before giving it to an application. This allows the contents of one application to leak into another. When the Chrome incognito window was closed, its framebuffer was added to the pool of free GPU memory, but it was not erased. When Diablo requested a framebuffer of its own, Nvidia offered up the one previously used by Chrome. Since it wasn’t erased, it still contained the previous contents. Since Diablo doesn’t clear the buffer itself (as it should), the old incognito window was put on the screen again.
Evan was also able to take advantage of the bug to write a small program that fetches all uncleared screenshots from GeForce framebuffers. This is a serious problem as it allows normal users to spy on the activities of other users without having to break the operating system security. Even worse, this can happen purely by accident like it did with Evan.
Evan only blogged about this problem this week, but he discovered and reported it to NVIDIA and Google 2 years ago. Google declared that this was NVIDIA's problem to fix and NVIDIA conceded and promised to fix it, but did nothing till now.
