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 18

Apple Expected to Release iOS 18.3 Next Week With These New Features

Thursday January 23, 2025 6:41 am PST by
iOS 18.3 should be released to the public next week, following beta testing since mid-December. While the software update is a relatively minor one, it still includes a handful of new features, changes, and bug fixes for iPhones. Below, we recap everything new in iOS 18.3. Notification Summary Changes Examples of inaccurate Apple Intelligence notification summaries Apple Intelligence...
Apple Pay Walmart Feature

Walmart Stands Firm on Why It Doesn't Accept Apple Pay in the U.S.

Thursday January 23, 2025 7:32 am PST by
Walmart still does not accept Apple Pay or other NFC payments at its more than 4,600 stores across the U.S., and it stood firm on its reasoning for that today. A spokesperson for Walmart today informed MacRumors that its position on contactless payments has not changed since we last reached out about the matter in 2022. The big-box retailer said it remains focused on its own convenient...
iOS 18

Here Are Apple's Full Release Notes for iOS 18.3

Tuesday January 21, 2025 4:31 pm PST by
Apple provided developers and public beta testers with the release candidate version of iOS 18.3 today, and with it comes release notes confirming what's new. While we knew about several of the features that are in the update, there are some lesser known tweaks and bug fixes. The update adds new Visual Intelligence features for iPhone 16 models, it tweaks Notification summaries on all...
truecaller

Truecaller iOS Update Rolls Out Real-Time Caller ID Support

Wednesday January 22, 2025 2:07 am PST by
Popular caller ID app Truecaller is rolling out an update that brings real-time caller ID support to its iOS subscribers. Apple introduced Live Caller ID Lookup in iOS 18, allowing third-party caller ID apps to securely retrieve information about a caller from their servers, hence today's Truecaller update. iPhone users can enable the Live Caller ID Lookup feature by going to Settings ➝ ...
iPhone 17 Air Size Feature

'iPhone 17 Air' With Rear Camera Bar Allegedly Shown in Leaked Photo

Tuesday January 21, 2025 12:46 pm PST by
A leaker known as "Majin Bu" today shared an alleged image of a component for the rumored, ultra-thin "iPhone 17 Air" model. The blurry, pixelated image shows a pair of rear iPhone shells with a pill-shaped, raised camera bar along the top. On the left side of the bar, there is a circular cutout that appears to be for a single rear camera. On the right side of the bar, there appears to be an ...
apple tv 4k new orange

New Apple TV Launching This Year With These New Features

Wednesday January 22, 2025 6:01 pm PST by
A new Apple TV is expected to be released later this year. In this article, we recap rumored features and changes for the device. 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 Wi-Fi 6E, which would be an upgrade over the current Apple TV's standard Wi-Fi 6 support. Wi-Fi 6E extends the...
Generic iOS 19 Feature Mock Light

iOS 19 Leak Reveals All-New Design

Friday January 17, 2025 2:42 pm PST by
iOS 19 is still around six months away from being announced, but a new leak has allegedly revealed a completely redesigned Camera app. Based on footage it obtained, YouTube channel Front Page Tech shared a video showing what the new Camera app will apparently look like, with the key change being translucent menus for camera controls. Overall, the design of these menus looks similar to...
iPhone SE 4 Single Camera Thumb 3

iOS 18.3 Leak Provides Clue About iPhone SE 4, iPad 11, and iPad Air 7 Launch Timing

Wednesday January 22, 2025 9:39 am PST by
New information has surfaced that indicates the rumored iPhone SE 4, iPad 11, and new iPad Air models are nearing launch. A private account on social media platform X today revealed that iOS 18.3 or iPadOS 18.3 will be preinstalled on all of those upcoming devices when they are released. It is still unclear exactly when the devices will launch, but this information suggests that Apple will...
iOS 18

5 New Things Your iPhone Can Do in iOS 18.3

Friday January 24, 2025 1:55 am PST by
Apple is set to release iOS 18.3 next week, bringing further refinements to Apple Intelligence features, a couple of neat new capabilities to iPhone 15 Pro and iPhone 16 devices, and bug fixes. While not quite as packed with new features as Apple's preceding iOS 18 point releases, iOS 18.3 still introduces capabilities that aim to make your iPhone smarter and more intuitive. Below, we've...

Top Rated Comments

GubbyMan Avatar
47 months ago
This will always be relevant https://xkcd.com/327/
Score: 64 Votes (Like | Disagree)
acorntoy Avatar
47 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
47 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
47 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
47 months ago
Changing my SSID right now to %s%s%s%p to test thi [user disconnected]
Score: 21 Votes (Like | Disagree)
bsolar Avatar
47 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)