FIFA 13 Ultimate Team's Web App has been hacked, forcing EA to take the service offline.
The Web App, which went live yesterday, allows players to manage and purchase their FIFA 13 Ultimate Team.
But an alleged exploit found in a Firefox plugin used to power the service has enabled users to gain unlimited access to free Ultimate Team packs, granting them rare and expensive players.
As well as gaining illegitimate access to rare players, users were then reportedly able to sell them at a low price, sending the virtual market into disarray.
The exploit is allegedly linked to Firefox's Tamper Data add-on.
Speaking on the official FIFA forum, EA Sports community manager Rob Hodson recognised the issue, saying:
"Our team has identified some new issues with the deployment of the FIFA ULTIMATE TEAM Web App.
"To ensure we can fix the issues we've identified, and ensure a stable experience for all users, the app will remain offline for some time. We'll continue to update you on when the Web App is back up and running."
EA Sports has yet to provide an ETA on when the web app will return or how it will handle players who have exploited the system.
Since the exploit was exposed, hundreds of people have voiced concerns on the game's official forums.
"You've really outdone yourselves this time EA," one user posted. "You've had weeks to prepare for the web-app launch, could have had it up and had trusted people testing to make sure it worked and there were no glitches, bugs, exploits, etc, but of course that would've required effort so you didn't do that, well played. Better luck next year."
In addition to the FIFA 13 Ultimate Team Web App, EA plans to launch an EA Sports Football Club app on iOS.
Want even more FIFA 13? Check out our FIFA 13 review for our verdict on this year's game.