iOS has a wireless network naming bug in it that effectively disables an iPhone’s ability to connect to WiFi. The bug was discovered by security researcher Carl Schou, who found that after joining a Wi-Fi network with the name “%p%s%s%s%s%n” his iPhone’s Wi-Fi functionality was left “permanently disabled.”
Changing a hotspot’s SSID did not correct the problem, even a reboot failed to provide a fix, says a report by BleepingComputer.
After joining my personal WiFi with the SSID “%p%s%s%s%s%n”, my iPhone permanently disabled it’s WiFi functionality. Neither rebooting nor changing SSID fixes it :~) pic.twitter.com/2eue90JFu3
— Carl Schou (@vm_call) June 18, 2021
Others that have reproduced the issue suggest that the bug could be related to the percentage sign at the start, which may be misinterpreted by iOS as a string-format specifier, indicating that characters following may be a variable or a command rather than plain text.
The issue only seems to affect iPhones, as Android devices don’t seem to be affected by the same network.
Luckily, there is a way to fix iPhones affected by the bug, but it requires a network settings reset.
To perform the reset, open the Settings app, tap General -> Reset, then tap Reset Network Settings and confirm the request at the prompt.