Hackers have managed to download Far Cry 3: Blood Dragon before its release. It appears to be thanks to a flaw in the uPlay online store, which has now been partially taken offline.

The game was only officially announced last week and is due for release on May 1st. It’s billed as an expansion to Far Cry 3, but can be played as a standalone game.

It appears a Russian-based hacking group have found a fairly simple flaw with Ubisoft’s online gaming store uPlay, which has an estimated 50 million registered users. Like several stores, the store uses a launcher to download and run games after purchase.

Using a specially crafted application, the hackers have found a way to trick uPlay into thinking you own a game that you haven’t bought, in turn allowing you to access a direct download link and then play it offline without any DRM checks.

While nosing round the servers, people exploiting this hack to help themselves found a copy of the Blood Dragon game, presumably already in place ready to be added to the purchasing menus next month.

The game appears to be complete and fully playable. Not surprisingly it’s already doing the rounds on torrent and other filesharing sites. There are also clips of up to 34 minutes of gameplay on sites such as YouTube, though you should note these contain spoilers.

Ubisoft has temporarily disabled game downloads for PCs and says they won’t be reactivated until the problem is fixed. It stresses that “no personal information was compromised” by the hacking.

Gameranx, which broke the news of the hacking, notes that Ubisoft may be able to tell which accounts are exploiting the flaw, in which case they’ll likely be banned from the service.