Caution! Wi-fi name makes your iPhone network unusable


Do you often dial into foreign WLAN networks with your iPhone? Then caution is not only required for data protection reasons. According to an investigation, specific wi-fi names can paralyze your iPhone wi-fi.

If you want to log into a new wi-fi network with your iPhone, there are usually two options: Either your login request is accepted or not – the latter, for example, because the password entered was not correct. But according to the latest findings, there is a third variant: The respective wireless network makes your iPhone WLAN unusable due to a specific WLAN designation (SSID).

Beware of the wi-fi name %p%s%s%s%s%n

Before you worry too much: The error only occurs with astonishing WLAN name variants. Security researcher Carl Schou came across the problem when he wanted to log in to his wi-fi network called “%p%s%s%s%s%n” with the iPhone. He used an iPhone XS with iOS 14.4.2.

During the login attempt, the WLAN of his iPhone suddenly switched off – and remained unusable as a result. In addition, it was no longer possible to send files from the iPhone to other Apple devices via AirDrop. All attempts to reactivate the iPhone’s wireless network failed. Even restarting the iPhone or changing the WLAN name on the router did not provide a solution.

Percent sign as the cause of the problem

The reason for the bug, according to previous findings, is the use of percent signs in the WLAN name. Above all, the percent symbol at the beginning should be a source of problems. The iPhone may interpret the % symbol as a program code. Since percent signs serve as placeholders in some programming environments, iOS could be confused in this regard, which in turn causes the described bug.

Reset WLAN settings

Currently, there is only one way to solve the problem. If your iPhone is affected, you have to reset its network settings (settings | General | Reset | Network settings). But beware: As a result, you lose all secured WI-FI connections and have to re-enter the WLAN password everywhere. By the way, Android doesn’t seem to be affected by the bug.