A bug in Apple's iOS has been discovered that can crash an iPhone by sending a single text message containing a certain string of characters.
The bug appears to be caused by a glitch in the way Apple's iOS software displays non-Latin text in notification banners and alerts.
When messages are previewed in banners, iOS adds an ellipsis to show there is more of the message to be viewed.
But if this is placed in the middle of a set of non-Latin characters, for example Arabic or Chinese, the system crashes and causes the phone to reboot.
Several users of online forum site Reddit discovered the flaw, which causes the iPhone receiving the message to crash and reboot as long as the recipient is not viewing the message conversation when the text is received.
In a statement, an Apple spokesman said: "We are aware of an iMessage issue caused by a specific series of unicode characters and we will make a fix available in a software update."
The bug appears to require a very specific set of characters to be sent, with those discussing the issue on Reddit reporting and sharing a single line of characters that cause the crash.
There are also reports that the bug is effective when sent using instant messaging service WhatsApp.
Though some users have reported the crash has caused them to be unable to access their messages, those on Reddit are using the bug as a prank rather than a serious breach of iPhone security.
Mark James, security specialist at anti-virus firm ESET said: "I am sure we have all had our desktop machines reboot after a seemingly random event has triggered the dreaded reboot. These mobile computers we call phones today have the same core instructions - if all else fails then reboot.
"This does not necessarily mean it's a security flaw or indeed an exploitable bug but Apple will none the less try and rectify this as soon as they possibly can."
However, Tim Erlin, director of product management at cyber security firm Tripwire, said: "The ability to remotely disable someone's iPhone could be useful in targeted attacks.
Imagine if an organisation's information security team was suddenly unable to communicate while an attack on their organisation was being carried out."
Many have reported that by turning off notification banners they have been able to avoid being affected by the bug, and that sending a photo to the contact who sent you the message, then clearing the conversation history, will remove the flaw.
Last year, a bug was discovered in photo-sharing app Snapchat that enabled attackers to flood an iPhone with information and crash it.