Just hours after the new Apple iPhone 5 was released, it has already been jailbroken. While iOS 6 has been jailbroken on other devices, this development means hackers have already found and exploited security holes to run custom code on the sixth-generation iPhone, which is the first device to actually ship with iOS 6.

iOS developer and hacker Grant Paul posted the following message on Twitter, which shows the iPhone 5 running the Cydia Store for jailbroken devices:

It’s certainly possible Paul faked the Cydia icon (by simply renaming a Web app and giving it the appropriate icon), or via some other clever trickery, but he stands by his claim. When Stefan Esser, another iOS hacker, asked about it directly, he said he had indeed jailbroken Apple’s latest and greatest:

On Wednesday, iOS 6 was released to the masses. On Thursday, Redmond Pie reported that iOS 6 had received a tethered jailbreak for the A4-based iPhone 4, the iPhone 3GS, and the 4th-generation iPod touch.

The iPhone 4S, the iPad 2, the iPad 3, and the 5th-generation iPod touch are not supported by that iOS 6 jailbreak. Furthermore, it’s a tethered jailbreak, meaning you have to boot into tethered-mode every time you reboot your device.

It’s thus very surprising to learn that on Friday (today), the A6-based iPhone 5 has already been jailbroken. We’ll be following this one closely.

Jailbreaking an iPhone, iPad, or iPod touch makes it possible to install apps that aren’t available in Apple’s App Store. Even if this jailbreak is confirmed by others in the community, the tools to do it for your own iPhone 5 won’t be available for a while. Nevertheless, this first step means the software will be developed sooner rather than later.

Update at 8:35PM EST: Paul has posted more proof of his feat.

Naysayers may still question the authenticity of this hack, but this should shut them up:

Quite an achievement!

See also: TNW’s Complete Review: iOS 6 bets big on Maps and Siri

Image credit: stock.xchng.