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

Apple Shopping Event 2025

Apple Announces 2025 Black Friday Event, Here's What You Can Get

Thursday November 20, 2025 6:28 am PST by
Apple's annual four-day Black Friday through Cyber Monday shopping event is returning on Friday, November 28 through Monday, December 1 in many countries, including the United States, Canada, Australia, New Zealand, France, Germany, Italy, Spain, the United Kingdom, Belgium, the Netherlands, Sweden, Thailand, and others. During the shopping event, customers can get an Apple gift card with...
iOS 26

iOS 26.2 Adds These New Features to Your iPhone

Thursday November 20, 2025 10:50 am PST by
iOS 26.2 is currently in beta testing. The upcoming update includes a handful of new features and changes on the iPhone, including a new Liquid Glass slider for the Lock Screen's clock, offline lyrics for Apple Music, and more. In a recent press release, Apple confirmed that iOS 26.2 will be released to all users in December, but it did not provide a specific release date. Keep reading...
hikawa phone grip stand apple%402x

Apple Launches Second Limited-Edition iPhone Accessory in a Month

Friday November 21, 2025 3:53 am PST by
Apple has begun selling the Hikawa Phone Grip and Stand, a new limited-edition iPhone accessory designed with accessibility in mind. Designed by LA-based Bailey Hikawa to celebrate the 40th anniversary of accessibility at Apple, the grip uses magnets to securely snap onto any iPhone with MagSafe. Apple says it can be removed with ease, and doubles as a stand with two different viewing...
iPhone 17 Pro Cosmic Orange

10 Reasons to Wait for Next Year's iPhone 18 Pro

Wednesday November 19, 2025 4:00 am PST by
Apple's iPhone development roadmap runs several years into the future and the company is continually working with suppliers on several successive iPhone models at the same time, which is why we often get rumored features months ahead of launch. The iPhone 18 series is no different, and we already have a good idea of what to expect for the iPhone 18 Pro and iPhone 18 Pro Max. One thing worth...
ipad black friday 2025

The Best Early Black Friday iPad Deals

Thursday November 20, 2025 10:20 am PST by
Black Friday is just over a week away, and iPad deals have finally started to flood in at retailers like Amazon and Best Buy. Below we're tracking discounts on every current generation iPad, including lowest-ever prices on M3 iPad Air and M5 iPad Pro, plus steep markdowns on iPad and iPad mini. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make a ...
ipad mini 7 feature red and blue

iPad Mini 8: Four Major New Features to Expect

Wednesday November 19, 2025 7:50 am PST by
Apple's eighth-generation iPad mini is highly likely to arrive next year, offering a significant refresh of the device with at least four major new features. OLED Display The next-generation version of the iPad mini could feature an OLED display, as part of Apple's plan to expand the display technology across many more of its devices. Apple's first OLED device was the Apple Watch in 2015, ...
watchos 26 workout app

Apple Watch Users Claim Workout App Is Now Worse in Every Way

Thursday November 20, 2025 7:01 am PST by
Apple Watch owners have been voicing their frustration online over changes to the Workout app that Apple introduced in watchOS 26, with many finding the redesigned interface makes starting exercises difficult and exasperating. When Apple launched watchOS 26 in September, the Workout app went from large, easily tapped workout tiles to a scrolling, corner-button interface. Instead of tapping a ...
Apple Foldable Thumb

Foldable iPhone to Debut These Two Breakthrough Features

Wednesday November 19, 2025 7:26 am PST by
Apple's first foldable iPhone is expected to launch alongside the iPhone 18 Pro models in fall 2026, and it's shaping up to include two standout features that could set it apart from the competition. The book-style foldable will reportedly feature an industry-first 24-megapixel under-display camera built into the inner display, according to a recent JP Morgan equity research report. That...
maxresdefault

The MacRumors Show: iPhone 18 Pro Looks Like a Huge Upgrade

Friday November 21, 2025 9:10 am PST by
On this week's episode of The MacRumors Show, we talk through all of the new features and improvements expected to come to next year's iPhone 18 Pro and iPhone 18 Pro Max models. Subscribe to The MacRumors Show YouTube channel for more videos Apple's next-generation iPhones are less than ten months away and we already have a good idea about what to expect based on corroborated leaks, rumors,...

Top Rated Comments

GubbyMan Avatar
58 months ago
This will always be relevant https://xkcd.com/327/
Score: 64 Votes (Like | Disagree)
acorntoy Avatar
58 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
58 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
58 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
58 months ago
Changing my SSID right now to %s%s%s%p to test thi [user disconnected]
Score: 21 Votes (Like | Disagree)
bsolar Avatar
58 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)