Apple did not immediately respond to enquiries for comment
A "text bomb" has been discovered which can crash iPhones just by being sent to a victim's device.
Software developer Abraham Masri discovered the bug and said he released it to get Apple's attention after his reports and warning to the company went unheeded.
The "text bomb" code is so toxic for iPhones that devices which were sent a link to the code would also crash - even if they didn't actually click the link.
Mr Masri has since unpublished the code, which has been called ChaiOS - a pun between the word "chaos" and iOS, Apple's mobile operating system.
As Mr Masri's code has been removed from GitHub, a developers' website, people are no longer able to send malicious texts linking to it.
"I'm not going to re-upload it. I made my point. Apple needs to take such bugs more seriously," he wrote.
Apple did not immediately respond to enquiries for comment.
It is possible that the code could be replicated by someone else and used to turn off phones - but at the moment, interrupting a phone is the only negative effect that the bug has.
The "text bomb" does not seem to be able to steal data or allow hackers to take control of others' iPhones.
ChaiOS is similar to a similar bug called Effective Power back in 2015.
That text bomb contained the word "Power" and caused the SpringBoard application - which manages the iOS home screen - to crash.