iPhone Wi-Fi Bug Causes Connection Failures with Specific Network Names

A newly discovered bug in iPhones can disrupt wireless connectivity when connecting to Wi-Fi networks with certain names. Even worse, Wi-Fi remains disabled after restarting the device or renaming the network. Security researchers warn that this vulnerability could be exploited by pranksters or malicious actors who set up rogue hotspots in public places, potentially blocking iPhones that attempt to connect.

How the Bug Was Discovered

Security researcher Carl Schou found the issue when he tried to connect his iPhone XS (running iOS 14.4.2) to his personal hotspot named “%p%s%s%s%s%n”. Upon attempting to connect, the iPhone’s Wi-Fi function was immediately disabled. Restarting the device or changing the hotspot’s name did not resolve the problem, and Wi-Fi could not be re-enabled.

Testing and Confirmation

Journalists from Bleeping Computer, after being informed by Schou, conducted their own tests and confirmed the bug. They found that connecting to a Wi-Fi network with a similar name caused the iPhone’s wireless connection to fail. The issue could not be reproduced on Android devices.

“In several tests, attempting to connect to such a strangely named SSID caused our Wi-Fi to malfunction, always resulting in the same outcome—loss of wireless connectivity. In some cases, we couldn’t connect to the SSID at all, and afterward, we were unable to access our regular wireless network. Other tests matched Schou’s experience, where Wi-Fi was disabled and could not be turned back on,” the journalists reported.

How to Fix the Issue

Researchers say the only way to resolve this bug is to completely reset the network settings on the affected iPhone.

Technical Details

The root of the problem appears to be a parsing error in iOS. When a Wi-Fi network name (SSID) contains the “%” character, iOS may mistakenly interpret the following letters as format specifiers. Schou admits he intentionally names his hotspots this way “to mess with poorly designed devices.”

Apple’s Response

As of now, Apple has not commented on the discovery of this bug.