An anonymous reader writes "We all knew it was just a matter of time, now it looks like Windows RT has been Jailbroken. From the article: 'The hack, performed by Clokr, exploits a vulnerability in the Windows kernel that has existed for a long time — since before Microsoft ported Windows from x86 to ARM, in fact. Basically, the Windows kernel on your computer is configured to only execute files that meet a certain level of authentication. There are four levels: Unsigned (0), Authenticode (4), Microsoft (8), and Windows (12). On your x86 Windows system, the default setting is Unsigned — you can run anything you like. With Windows RT, the default, hard-coded setting is Microsoft (8); i.e. only apps signed by Microsoft, or parts of Windows itself, can be executed.'"