Apple released a new version of its mobile platform, iOS 10.3.3, on Wednesday, fixing a couple of security issues. Sounds like business as usual, but one of the bugs squashed with this update was actually quite serious.

The issue, first reported by security expert Nitay Artenstein, let attackers execute arbitrary code on the Wi-Fi chip of an iPhone, iPad or an iPod touch.

That particular bug, dubbed Broadpwn, is different from most security vulnerabilities as it requires zero user interaction. In other words, if you're in Wi-Fi range of an attacker and have Wi-Fi on, he can essentially take over your phone.

The bug affects Broadcom's BCM43xx family of chips and is thus present in an enormous range of devices, including many Android phones (Google issued a patch for Android devices in early July). On the iOS front, iPhone 5 and later, iPad 4 and later, and the sixth generation iPod touch are affected.

As a user, there's nothing you need to do except accept the 10.3.3 update. Choosing not to do so will leave your phone wide open to malicious hackers.

Vulnerabilities as severe as this one are rare, as the Wi-Fi chip is separate from the device's main processor and it's hard to escalate a vulnerability from one to the other. Artenstein will describe how he did it at the Black Hat conference. His talk is scheduled for July 27.