Apple Accidentally Unpatches Vulnerability, Leading to New iOS 12.4 Jailbreak

Apple in iOS 12.4 mistakenly unpatched a vulnerability that was fixed in the iOS 12.3 update, leading to a new jailbreak available for iOS 12.4 devices, reports Motherboard.

Hackers discovered the vulnerability over the weekend and Pwn20wnd created a publicly available, free jailbreak that works on devices running the latest version of iOS or any version of iOS below iOS 12.3.

unc0ver jailbreak 12 4
Most jailbreak code is kept private to keep Apple from patching it, so this is the first time that a public jailbreak has been available in a while. It was apparently discovered when a user tested an older jailbreak on iOS 12.4 and found the patch had been reverted.

Security researcher Jonathan Levin told Motherboard that the accidental vulnerability also once again makes iPhone users vulnerable to a "100+ day exploit," referring to how long the bug has been around.

Ned Williamson from Google Project Zero said that the bug could be exploited to install spyware on a target ‌iPhone‌.

The researcher told Motherboard that "somebody could make a perfect spyware" taking advantage of Apple's mistake. For example, he said, a malicious app could include an exploit for this bug that allows it to escape the usual iOS sandbox--a mechanism that prevents apps from reaching data of other apps or the system--and steal user data.

Another scenario is a hacker including the exploit in a malicious webpage, and pairing it with a browser exploit, according to the researcher.

A third security researcher, Stefan Esser said that people should be careful what apps they download from the App Store right now. "Any such app could have a copy of the jailbreak in it," he wrote on Twitter.

Multiple users have confirmed that the jailbreak works and that their devices have been jailbroken using the new software. Apple has not commented on how or why the vulnerability was unpatched, but the company will likely have a fix available soon.

Popular Stories

iPhone 17 Pro Dark Blue and Orange

iPhone 17 Release Date, Pre-Orders, and What to Expect

Thursday August 28, 2025 4:08 am PDT by
An iPhone 17 announcement is a dead cert for September 2025 – Apple has already sent out invites for an "Awe dropping" event on Tuesday, September 9 at the Apple Park campus in Cupertino, California. The timing follows Apple's trend of introducing new iPhone models annually in the fall. At the event, Apple is expected to unveil its new-generation iPhone 17, an all-new ultra-thin iPhone 17...
iPhone 17 Pro Iridescent Feature 2

iPhone 17 Pro Clear Case Leak Reveals Three Key Changes

Sunday August 31, 2025 1:26 pm PDT by
Apple is expected to unveil the iPhone 17 series on Tuesday, September 9, and last-minute rumors about the devices continue to surface. The latest info comes from a leaker known as Majin Bu, who has shared alleged images of Apple's Clear Case for the iPhone 17 Pro and Pro Max, or at least replicas. Image Credit: @MajinBuOfficial The images show three alleged changes compared to Apple's iP...
xiaomi apple ad india

Apple and Samsung Push Back Against Xiaomi's Bold India Ads

Friday August 29, 2025 4:54 am PDT by
Apple and Samsung have reportedly issued cease-and-desist notices to Xiaomi in India for an ad campaign that directly compares the rivals' devices to Xiaomi's products. The two companies have threatened the Chinese vendor with legal action, calling the ads "disparaging." Ads have appeared in local print media and on social media that take pot shots at the competitors' premium offerings. One...
iphone 16 pro ghost hand

iPhone 17 Pro: 5 Reasons Not to Upgrade This Year

Monday September 1, 2025 4:35 am PDT by
Apple will launch its new iPhone 17 series this month, 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 to...
iOS 18 on iPhone Arrow Down

Apple Preparing iOS 18.7 for iPhones as iOS 26 Release Date Nears

Sunday August 31, 2025 4:35 pm PDT by
Apple is preparing to release iOS 18.7 for compatible iPhone models, according to evidence of the update in the MacRumors visitor logs. We expect iOS 18.7 to be released in September, alongside iOS 26. The update will likely include fixes for security vulnerabilities, but little else. iOS 18.7 will be one of the final updates ever released for the iPhone XS, iPhone XS Max, and iPhone XR,...

Top Rated Comments

Wiencon Avatar
79 months ago
Honest question... do people still really jailbreak like that? Like, how big is the jailbreak community now?
I love questions like that. Yeah, the community is quite big, the jailbreak subreddit has over 300k subscribers and after last couple of releases it seems to be gathering some popularity.

Stock iOS 12 is great, but jailbreaking it is a no-brainer for me, especially when we can jailbreak the newest and signed version (which is a very rare opportunity)
I can tell you why I jailbreak all my iOS devices (SE and two X's)

- You can get real split screen multitasking with the https://www.idownloadblog.com/2019/04/23/pullover-pro/

- You can have ANY app on the CarPlay screen with https://www.redmondpie.com/carbridge-for-ios-12-jailbreak-released-lets-you-use-any-app-with-carplay/

- You can get all iPhone X gestures on older devices without any lags, bugs, with the https://www.idownloadblog.com/2019/03/18/neptune-for-iphone/

- You can have customizable Answering machine, record messages to the device and even set different greetings for different callers with https://www.idownloadblog.com/2018/08/23/answeringmachine-x/

- You can get rid of the full screen calling screen which users have been asking for ages with https://www.idownloadblog.com/2019/03/06/callbar-xs-brings-everyones-favorite-phone-call-centric-jailbreak-tweak-to-ios-12/

- You can stack icons together instead of using folders which looks extremely cool with https://www.idownloadblog.com/2018/12/03/zenith/

- You can get amazing gestures in app switcher screen with https://www.idownloadblog.com/2019/05/04/gesto/

- You can get the grid switcher from iPad in your iPhone with https://www.idownloadblog.com/2019/03/11/newgridswitcher/

- You can have custom shortcuts on lockscreen with the https://www.idownloadblog.com/2018/04/20/jumper/

- You can write notes on your lockscreen with the https://www.idownloadblog.com/2018/08/30/notepad/

- And hundreds of small things

Jailbreaking is not only about some themes, you can really get the 100% from your iPhones instead of the 60% or less that Apple gives you.
My jailbroken SE can do more than stock XS (without any performance issues) and that is not an exaggeration

I think that now is an amazing opportunity to try jailbreaking, you have nothing to lose. If anything happens (which is extremely unlikely because jailbreaks now aren't permanent/untethered) you can easily restore your device to the newest stock iOS version with iTunes and forget about everything
Score: 30 Votes (Like | Disagree)
Unity451 Avatar
79 months ago
I really wish that I had the surplus of time that hackers always seem to have.
Score: 20 Votes (Like | Disagree)
jsmith189 Avatar
79 months ago
Honest question... do people still really jailbreak like that? Like, how big is the jailbreak community now?
Score: 16 Votes (Like | Disagree)
AppleFan91 Avatar
79 months ago
I wish Apple was on its game, but alas, no. It's a company spread too thin, governed by greedy hand-wringers.
Yes yes, and Apple is doomed and Steve is rolling in his grave like a gas station hotdog
Score: 13 Votes (Like | Disagree)
mannyvel Avatar
79 months ago
I'm surprised this regression happened. This points to a breakdown in product management discipline, which in general is a bad sign.
Score: 12 Votes (Like | Disagree)
BarredOwl Avatar
79 months ago
I wish Apple was on its game, but alas, no. It's a company spread too thin, governed by greedy hand-wringers.
Score: 11 Votes (Like | Disagree)