Since as early as the beginning of 2017, iOS has reportedly had a censorship function in which switching an iPhone's location setting to China -- which doesn't recognize Taiwan to be an independent entity -- makes the Taiwanese flag emoji disappear. Any text that features the emoji just shows a "missing" emoji.
But security researcher Patrick Wardle found that sometimes, a bug in the code would consider the Taiwan emoji to be an invalid input, rather than missing from the phone's library, according to Wired. That caused iPhones to crash.
Wardle informed Apple about the bug and helped the company fix it, which Apple noted in a security update on Monday. The company wrote that "a denial of service issue was addressed with improved memory handling." Apple didn't immediately respond to a request for comment.
The bug enabled anyone to crash a vulnerable device by merely sending a text message with the Taiwanese flag.
Apple has reportedly catered to the Chinese government before, moving Chinese Apple users' data to servers within the country and getting rid of some VPNS from the App Store in China.
In contrast, the company was also involved in a dispute with the FBI over encryption in 2016 after it refused to unlock a terrorist's iPhone for law enforcement.
"They say 'we're not going to spy on our users.' But if China asks, they'll build censorship into their devices and not really talk about it," Wardle told Wired. "Hypocrisy is the term I would use."