It's yet to go live on the magazine's website, [Update: it is now] but the latest issue of Game Informer is now available for download for some digital subscribers. And the game on the cover is the previously unannounced The Witcher 3.
The image is legitimate; Zinio's subscription page confirms The Witcher 3 is this month's cover feature.
Bigger version of the image below. So you can see that beard.
Some preliminary info supposedly contained in the article, courtesy of a NeoGAF user Indigo Cyclops with a Zinio subscription (my subscription is via the App Store, where this issue isn't available):
World supposedly 20% bigger than Skyrim's
30-40 minutes to cross world on Horseback
New streaming technology (CDRED Engine 3)
Geralt's Memory is restored
No chapters/acts
Dude is fucking DONE fighting for everyone else
Everything from solving MYSTERIES to slaying monsters
Coming out on "all top-of-the-line" consoles—I'd say that confirms next-gen is in.
The world would be a better place if that's what actual press releases looked like.
UPDATE - Game Informer has gone live with its official announcement. Alongside more artwork, there's clearer word on the game's size, the report saying it's "30 times larger than the previous game—an enormous setting even larger than Skyrim's vast expanse, made possible with the new REDengine 3 technology that developer CD Projekt RED is debuting with the game."
They also say that, alongside the PC, the game will be released on "all high-end platforms available", which is about as close to "those next-gen consoles that haven't been announced yet" as you're going to get from a developer.