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

iOS 26 on iPhone Feature

Here's When iOS 26 Rolls Out Today in Every Time Zone [Update: Out Now!]

Monday September 15, 2025 12:00 am PDT by
Update 10:06 a.m.: iOS 26 is rolling out now, though it may take a bit for all users to see it, so keep checking! Today's the day! Apple is about to release iOS 26, which will deliver the biggest redesign since iOS 7 and bring a range of new features and improvements to iPhones worldwide. It's Apple's biggest software update of the year, and Apple announced at last week's iPhone event that...
Tim Cook Rainbow

Apple Reportedly Plans to Launch These 10 Products in 'Coming Months'

Sunday September 14, 2025 8:45 am PDT by
Apple's annual September event is now in the rearview mirror, with the iPhone 17, iPhone 17 Pro, iPhone 17 Pro Max, iPhone Air, Apple Watch Series 11, Apple Watch Ultra 3, Apple Watch SE 3, and AirPods Pro 3 set to launch this Friday, September 19. As always, there is more to come. In his Power On newsletter today, Bloomberg's Mark Gurman said Apple plans to release many products in the...
iOS 26 Battery Glass Feature

Apple Says Installing iOS 26 Might Impact Battery Life

Monday September 15, 2025 10:56 am PDT by
In the iOS 26 release notes, Apple is warning iPhone users that installing the new software might have a temporary impact on battery life, which is normal. A new support document explains that major iOS updates require background setup like indexing data and files for search, downloading new assets, and updating apps. Further, Apple says that new features could require more resources,...
apple n1 chip

Apple's New N1 Chip in iPhone 17, iPhone 17 Pro, and iPhone Air Has a Wi-Fi 7 Limitation

Saturday September 13, 2025 10:01 am PDT by
The latest iPhone 17, iPhone 17 Pro, iPhone 17 Pro Max, and iPhone Air models are equipped with Apple's all-new N1 chip for Wi-Fi 7, Bluetooth 6, and Thread connectivity. However, the chip has a Wi-Fi 7 bandwidth limitation. According to FCC documents reviewed by MacRumors, the N1 chip in all of the new iPhone models supports up to 160 MHz channel bandwidth for Wi-Fi 7, short of the...
iphone 17 lineup

iPhone 17 Models Launch on September 19 With These New Features

Friday September 12, 2025 7:58 am PDT by
Apple will launch its new iPhone 17 lineup and ultra-thin iPhone Air in stores on Friday, September 19, and the company has already shown off the new devices at its fall event, which ran with the the tagline "Awe dropping." The iPhone 17 series brings a host of new features and enhancements. Here's a rundown of the biggest upgrades and changes: iPhone 17 Display Changes The iPhone...
AirPods Pro Firmware Feature

AirPods Pro 2 and AirPods 4 Get iOS 26 Features With New Firmware Update

Monday September 15, 2025 10:50 am PDT by
Apple today released updated firmware for the AirPods Pro 2 and the AirPods 4, introducing support for the new AirPods features that are included in iOS 26, iPadOS 26, and macOS Tahoe. The firmware has a build number of 8A356, and it replaces the current 7E93 firmware. With Apple's new software updates, the AirPods Pro 2 and the AirPods 4 support better audio quality for phone calls and...
iPhone 17 Pro Air Boxes

iPhone Air and iPhone 17 Pro Boxes Revealed

Sunday September 14, 2025 1:36 pm PDT by
T-Mobile President Jon Freier today shared real-world photos of Apple's boxes for the iPhone Air, iPhone 17 Pro, and iPhone 17 models, which launch on Friday. Image Credit: Jon Freier Apple has typically included iPhone box renders in its product environmental reports, but it did not do so for the latest models. However, Apple's iPhone Upgrade Program page does offer some images of the boxes, ...

Top Rated Comments

GubbyMan Avatar
55 months ago
This will always be relevant https://xkcd.com/327/
Score: 64 Votes (Like | Disagree)
acorntoy Avatar
55 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
55 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
55 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
55 months ago
Changing my SSID right now to %s%s%s%p to test thi [user disconnected]
Score: 21 Votes (Like | Disagree)
bsolar Avatar
55 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)