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Corrupt video causes all iPhones to crash, forcing a hard reboot Getty Images

A corrupted video being shared online will crash any iPhone or iPad it is played on, and in some cases causes the device to switch off and become unresponsive.

The video, which IBTimes UK will not be linking to, is an .mp4 file which can be played in the iOS Safari web browser, but quickly slows the device to a crawl, before causing it to lock up and freeze.

Discovered by YouTuber Everything ApplePro, the flaw is being described as "completely crazy" and will crash any iOS device. It comes a year after a certain text message was discovered to crash and reboot iPhones whenever it was received.

But where the text bug caused the iPhone to reboot, the newly discovered video file crashes the phone to such an extent that only a hard reset (holding the power and home buttons) will bring the phone back to life.

The bug is said to "not have any long-lasting effects," but causes a huge number of iOS devices to crash, dating all the way back to iOS 5, which came out in 2011. iPhones running the iOS 10.3 beta, which is not yet available to the public, shut off and display the spinning icon, normally shown when switching off, indefinitely.

The video, which is just three seconds long, plays fine but then the targeted iPhone starts to slow down and eventually become unresponsive; at this point, the screen and buttons no longer work.

As 9to5Mac suggests, this is happening because the video is corrupt and is leaking memory. "The likely reason is that it's simply a corrupted video that's some sort of memory leak and when played, iOS isn't sure how to properly handle it," the Apple blog said.

To hard reset and fix an iPhone 7, you need to press and hold the power and volume down button until the Apple logo appears and the phone reboots. On all other iPhones, you must press and hold the home and power buttons for 10 seconds.