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This bizarre iPhone bug can permanently disable your Wi-Fi

Published Jun 21st, 2021 7:31AM EDT
iPhone Wi-Fi Bug
Image: New Africa/Adobe

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Joining public Wi-Fi networks you don’t trust is a practice you should teach yourself to avoid to improve your privacy. Even when getting on the coffee shop or hotel’s complimentary Wi-Fi network, you should consider enabling a VPN service to protect your internet traffic. The more paranoid might want to leave that premium VPN connection on at all times, even when home, at the office, or when connecting to Wi-Fi networks belonging to friends and family. Alternatively, if your cellular plan comes with a great data package or unlimited internet, you could surf the web only over 4G or 5G while keeping active that VPN connection.

Incidentally, avoiding foreign Wi-Fi networks will also help you avoid an unexpected Wi-Fi bug that might render your iPhone’s ability to connect to Wi-Fi useless. That’s because you’d avoid an incredibly rare type of Wi-Fi network name that ruins Wi-Fi connectivity on iOS until a network reset is performed.

Security researchers often discover freak events that would trigger an unexpected behavior on some gadgets. This Wi-Fi issue is similar to all those text messages containing strange character sequences that could freeze the iPhone for a limited time.

We’re now looking at what must be an incredibly rare Wi-Fi network name %p%s%s%s%s%n, which security researcher Carl Schou found. As you’ll see in the following video, the Wi-Fi functionality is left permanently disabled after joining that particular Wi-Fi name.

The first “%” symbol in the Wi-Fi network’s name above might be guilty of the bug, MacRumors explains. iOS might interpret that first “%” as a string-format specifier, and this could lead to the behavior seen in the video.

A permanent fix might be available when Apple fixes this type of unexpected Wi-Fi bug, but users who want to replicate it might discover they can’t fix it themselves without suffering some data loss. Rebooting the phone or changing the SSID will not work. The one thing that will reenable Wi-Fi connectivity is resetting the iPhone’s network settings. To perform the network reset, you’ll need to head to Settings and then choose the Reset menu from the list. On the next page, look for the Reset Network Settings option and follow the instructions.

That sort of reset will erase all of the stored Wi-Fi passwords you might have saved on the device. If you have a very recent iPhone backup, you might consider restoring from that backup to regain your lost Wi-Fi passwords, but that might lead to app data loss elsewhere on the handset. Otherwise, you’ll have to input Wi-Fi passwords manually as you connect to nearby networks.

The bug doesn’t impact Android devices, only iPhones. It’s likely that iPads will behave similarly when connected to Wi-Fi networks with the name seen above.

Chris Smith Senior Writer

Chris Smith has been covering consumer electronics ever since the iPhone revolutionized the industry in 2008. When he’s not writing about the most recent tech news for BGR, he brings his entertainment expertise to Marvel’s Cinematic Universe and other blockbuster franchises.

Outside of work, you’ll catch him streaming almost every new movie and TV show release as soon as it's available.