iOS 5, which you'll recall was announced but a day or so ago by Steve Jobs at WWDC, has already been cracked open by serial jailbreakers, iPhone Dev Team (just a confusing name - they're nothing to do with Apple's actual iPhone developers).
A member of the group tweeted on Tuesday night that the beta release of iOS 5, which had so far only been released to app developers, is vulnerable to an already-existing exploit in iOS software.
Jailbroken iDevices allow users to install modified versions of Apple's operating systems and run third party apps not hosted on the App Store. Two screenshots posted by the jailbreak group show what they claim to be an iPod Touch running a jailbroken iOS 5, evidenced by the icon for the Cydia app store - a separate app store only available on jailbroken Apple devices.
It's not all bad news for Apple, though - iOS 5 won't be released to the public until the Autumn, and if part of the point of beta testing is to spot flaws in the final product, then iOS 5 is performing its job admirably.
Apple iOS 5 video: 10 things you need to know