iOS Bug Causes Specific Network Name to Disable Wi-Fi on iPhones

A wireless network naming bug has been discovered in iOS that effectively disables an iPhone's ability to connect to Wi-Fi.

ios wifi settings
Security researcher Carl Schou 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 nothing to correct the problem, with even a reboot failing to make a difference, according to BleepingComputer.

Other users who were able to replicate the issue have suggested the bug could be related to the initial use in the network name of the percentage sign, which leads to an input parsing issue whereby iOS mistakenly interprets the letters following the "%" as a string-format specifier.


In C and C-style languages, string format specifiers have a special meaning and are parsed by the language compiler as a variable name or a command instead of standard text.

Android phones don't seem to be affected by the same network, but iPhones hit by the problem need to have their network settings reset before a Wi-Fi hotspot can be connected again.

To perform the reset, open the Settings app, tap General -> Reset, then tap Reset Network Settings and confirm the request at the prompt.

Popular Stories

iphone 16 pro ghost hand

5 Reasons to Skip This Year's iPhone 17 Pro

Thursday July 10, 2025 4:54 am PDT by
Apple will launch its new iPhone 17 series in two months, and the iPhone 17 Pro models are expected to get a new design for the rear casing and the camera area. But more significant changes to the lineup are not expected until next year, when the iPhone 18 models arrive. If you're thinking of trading in your iPhone for this year's latest, consider the following features rumored to be coming...
apple tv 4k new orange

New Apple TV Expected Later This Year With These New Features

Saturday July 12, 2025 3:09 pm PDT by
A new Apple TV is expected to be released later this year, and a handful of new features and changes have been rumored for the device. Below, we recap what to expect from the next Apple TV, according to rumors. Rumors Faster Wi-Fi Support The next Apple TV will be equipped with Apple's own combined Wi-Fi and Bluetooth chip, according to Bloomberg's Mark Gurman. He said the chip supports ...
iPhone 17 Pro in Hand Feature Lowgo

iPhone 17 Pro Coming Soon With These 16 New Features

Friday July 11, 2025 12:40 pm PDT by
Apple's next-generation iPhone 17 Pro and iPhone 17 Pro Max are only two months away, and there are plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models. Latest Rumors These rumors surfaced in June and July:A redesigned Dynamic Island: It has been rumored that all iPhone 17 models will have a redesigned Dynamic Island interface — it might ...
macbook pro blue green

M5 MacBook Pro No Longer Coming in 2025

Thursday July 10, 2025 12:38 pm PDT by
Apple does not plan to refresh any Macs with updated M5 chips in 2025, according to Bloomberg's Mark Gurman. Updated MacBook Air and MacBook Pro models are now planned for the first half of 2026. Gurman previously said that Apple would debut the M5 MacBook Pro models in late 2025, but his newest report suggests that Apple is "considering" pushing them back to 2026. Apple is now said to be...
iphone 16 pro pro max

iPhone 17 Pro Models With BOE Displays Will Be Sold in China Only

Thursday July 10, 2025 11:59 pm PDT by
iPhone 17 Pro and iPhone 17 Pro Max models with displays made by BOE will be sold exclusively in China, according to a new report. Last week, it emerged that Chinese display manufacturer BOE was aggressively ramping up its OLED production capacity for future iPhone models as part of a plan to recapture a major role in Apple's supply chain. Now, tech news aggregator Jukan Choi reports...
Apple Watch Ultra 2 Complications

Apple Watch Ultra 3: What to Expect

Sunday July 13, 2025 10:30 am PDT by
The long wait for an Apple Watch Ultra 3 is nearly over, and a handful of new features and changes have been rumored for the device. Below, we recap what to expect from the Apple Watch Ultra 3:Satellite connectivity for sending and receiving text messages when Wi-Fi and cellular coverage is unavailable 5G support, up from LTE on the Apple Watch Ultra 2 Likely a wide-angle OLED display that ...
apple wallet drivers license feature iPhone 15 pro

Apple Says iPhone Driver's Licenses Will Expand to These 8 U.S. States

Tuesday July 8, 2025 11:26 am PDT by
In select U.S. states, residents can add their driver's license or state ID to the Wallet app on the iPhone and Apple Watch, providing a convenient and contactless way to display proof of identity or age at select airports and businesses, and in select apps. Unfortunately, this feature continues to roll out very slowly since it was announced in 2021, with only nine U.S. states, Puerto Rico,...
iPhone 17 Air Colors Thumb 2

iPhone 17 and iPhone 17 Air Rumored to Come in These 9 Colors

Friday July 11, 2025 12:30 am PDT by
The iPhone 17 and iPhone 17 Air will be available in a total of nine color options, according to new information coming out of Asia. The iPhone 17 Air's expected color options. According to the leaker going by the account name "yeux1122" on the Korean blog Naver, accessory manufacturers are now producing camera protector rings for the iPhone 17 and iPhone 17 Air in colors to match their...

Top Rated Comments

GubbyMan Avatar
53 months ago
This will always be relevant https://xkcd.com/327/
Score: 64 Votes (Like | Disagree)
acorntoy Avatar
53 months ago
Now Macrumors has led this from ~10 affected idiots to ~10,000. I encourage you to try it though, your device might be special and immune.
Score: 47 Votes (Like | Disagree)
Carlson-online Avatar
53 months ago
Pretty sure of course this big will effect nobody as who would use that as a network name ?!
Score: 22 Votes (Like | Disagree)
PinkyMacGodess Avatar
53 months ago
The real question is why would iOS do anything with the SSID? It's a 'string'. If iOS is choking on it, it shouldn't be looking at it as filet mignon! (Bad analogy warning?) It's like eating the wrapper your hamburger came in. Come on Apple...
Score: 21 Votes (Like | Disagree)
JetLaw Avatar
53 months ago
Changing my SSID right now to %s%s%s%p to test thi [user disconnected]
Score: 21 Votes (Like | Disagree)
bsolar Avatar
53 months ago

Agreed. Who cares about a bug that will effect literally one person out of 1 billion, when there are bigger fish to fry.
It affects basically nobody as long as it's just a joke SSID encountered by chance, but it highlights a vulnerability in the software which malicious actors can further investigate and potentially have the chance to further exploit.

That's why Apple should promptly fix the root issue before worse exploits have a chance to happen.
Score: 21 Votes (Like | Disagree)