iOS 15.2.1 and iPadOS 15.2.1 Address HomeKit Vulnerability

Apple today released iOS 15.2.1 and iPadOS 15.2.1, minor updates that include an important security fix for a known HomeKit vulnerability that was first discovered last year.

homekit showdown 2 thumb
According to Apple's security support document for the update, it addresses an issue that could cause a maliciously crafted ‌HomeKit‌ name to result in a denial of service, causing iPhones and iPads not to work.

Apple says that it was caused by a resource exhaustion issue that has now been addressed with improved input validation.


The ‌HomeKit‌ bug was first highlighted in January by Bleeping Computer after being discovered by Trevor Spiniolas. Called "doorLock," the vulnerability is executed by changing the name of a ‌HomeKit‌ device to something with over 500,000 characters.

Attempting to load such a large string of characters causes the iOS device to be sent into a denial of service state, and a forced reset is the only way to recover. Resetting the device results in a loss of data unless there is an available backup, and signing back into an affected iCloud account linked to the broken ‌HomeKit‌ device name can re-trigger the bug.

Apple partially fixed the bug in iOS 15.1 by limiting the length of the name that can be set for a ‌HomeKit‌ device or app, but it didn't entirely fix the issue because malicious people exploiting the vulnerability could use Home invitations rather than a device to trigger the attack.

Because this bug could result in data loss at worst and a device reset at best, it's worth updating to the iOS and iPadOS 15.2.1 updates right away.

Related Roundups: iOS 15, iPadOS 15
Related Forum: iOS 15

Top Rated Comments

hackedmac Avatar
19 weeks ago
Does this fix the Snapshots not updating on the cameras?
Score: 8 Votes (Like | Disagree)
PBG4 Dude Avatar
19 weeks ago

Who really would have created a HomeKit device with a name over 500,000 characters? While it's possible, it's INCREDIBLY unlikely.
The problem isn’t that someone could name an object with >500K characters. The problem is Apple code is willing to accept inputs of this length, even when the field has not had the memory allocated to handle a 500K length string.
Score: 7 Votes (Like | Disagree)
Sydnxt Avatar
19 weeks ago
Wow, no release notes on the software update screen!
Score: 6 Votes (Like | Disagree)
d4cloo Avatar
19 weeks ago

I'm a heavy critic on how Apple developed HomeKit. I see I'm getting validated today.
I'm mostly annoyed by the user experience. I have a lot of smart equipment, and it's extremely cumbersome and frankly impossible to design a custom screen in Control Center that is laid out exactly according to my preferences.
Score: 6 Votes (Like | Disagree)
Macintosh TV Avatar
19 weeks ago
Who really would have created a HomeKit device with a name over 500,000 characters? While it's possible, it's INCREDIBLY unlikely.
Score: 5 Votes (Like | Disagree)
doboy Avatar
19 weeks ago
Seriously, people accept home invitations from randos? Haha.
Score: 4 Votes (Like | Disagree)

Related Stories

powerdir exploit microsoft

Microsoft Discovered New 'Powerdir' macOS Vulnerability, Fixed in 12.1 Update

Monday January 10, 2022 9:17 am PST by
Microsoft's 365 Defender Research Team this morning published details on a new "Powerdir" macOS vulnerability that let an attacker bypass the Transparency, Consent, and Control technology to gain unauthorized access to protected data. Apple already addressed the CVE-2021-30970 vulnerability in the macOS Monterey 12.1 update that was released in December, so users who have updated to the...
ipad iphone duo ios 12

Apple Releases iOS and iPadOS 12.5.4 Security Fix for Older iPhones and iPads

Monday June 14, 2021 10:15 am PDT by
Apple today released new iOS and iPadOS 12.5.4 updates, with the new software aimed at older devices that are unable to run the iOS 14 update that's available on modern devices. The iOS and iPadOS 12.5.4 updates can be downloaded for free and the software is available on all eligible devices over-the-air in the Settings app. To access the new software, go to Settings > General > Software...
ios 15

Apple Releases Minor iOS 15.2.1 and iPadOS 15.2.1 Updates

Wednesday January 12, 2022 10:05 am PST by
Apple today released minor 15.2.1 updates for iPhone and iPad users, and the software comes one month after Apple launched iOS 15.2 and iPadOS 15.2 with a slew of improvements. The iOS 15.2.1 and iPadOS 15.2.1 update can be downloaded for free and the software is available on all eligible devices over-the-air in the Settings app. To access the new software, go to Settings > General >...
iOS 15

Apple Stops Signing iOS 15.3.1 Following iOS 15.4 Release, Downgrading No Longer Possible

Tuesday March 22, 2022 5:12 pm PDT by
Following the release of iOS 15.4 on March 14, Apple has stopped signing iOS 15.3.1, the previously available version of iOS that came out in February. As iOS 15.3.1 is no longer being signed, it is not possible to downgrade to that version of iOS if you've updated to iOS 15.4. Apple routinely stops signing older versions of software updates after new releases come out in order to encourage...
iOS 14 on iPhone feature emergency

Apple Releases iOS 14.8.1 and iPadOS 14.8.1 With Security Updates

Tuesday October 26, 2021 11:50 am PDT by
Apple today released iOS and iPadOS 14.8.1, minor updates to the iOS and iPadOS 14 operating systems. iOS and iPadOS 14.8.1 come more than a month after the release of iOS and iPadOS 14.8, another security fix update. The iOS and iPadOS 14.8.1 updates can be downloaded for free and the software is available on all eligible devices over-the-air in the Settings app. To access the new software, ...
safari icon blue banner

macOS Monterey 12.2 and iOS 15.3 Release Candidates Fix Safari Bug That Leaks Browsing Activity

Thursday January 20, 2022 1:30 pm PST by
The macOS Monterey 12.2 and iOS 15.3 release candidates that came out today appear to address a Safari bug that could cause your recent browsing history and details about your identity to be leaked to malicious entities. As shared last week by browser fingerprinting service FingerprintJS, there is an issue with the WebKit implementation of the IndexedDB JavaScript API. Any website that uses...
HomeKit Camera Thumbnails

iOS 15.3 Fixes Issue With HomeKit Camera Thumbnails Failing to Refresh

Thursday January 27, 2022 6:22 am PST by
Apple released iOS 15.3 and iPadOS 15.3 on Wednesday with several security fixes, and we have since learned that the software updates also resolve an issue with HomeKit camera thumbnails failing to refresh for some users in the Home app. HomeKit Secure Video cameras added to the Home app each have a thumbnail that provides a still view of recent footage, and normally these thumbnails...
iOS 15

Apple Seeds Release Candidate Version of iOS 15.4 and iPadOS 15.4 to Developers and Public Beta Testers

Tuesday March 8, 2022 11:19 am PST by
Apple today seeded the release candidate versions of upcoming iOS 15.4 and iPadOS 15.4 updates to developers for testing purposes, with the new software coming one week after Apple seeded the fifth betas of iOS 15.4 and iPadOS 15.4. The RCs represent the final versions of the updates that will be released to the public next week. Developers can download iOS 15.4 and iPadOS 15.4 through the...

Popular Stories

iPhone 14 Pro Purple Front and Back MacRumors Exclusive

iPhone 14 Pro Renders Highlight Multiple Design Changes

Wednesday May 25, 2022 8:56 am PDT by
Leaker Jon Prosser today shared ostensibly accurate renders of the iPhone 14 Pro, providing the most accurate look yet at what the device could look like when it launches later this year. In the latest video on YouTube channel Front Page Tech, Prosser revealed renders of the iPhone 14 Pro made by Apple concept graphic designer Ian Zelbo, highlighting a range of specific design changes...
iPad Pro USB C Feature Coral

Deals: Apple's iPad Pro Reaches Up to $449 Off in Amazon's Latest Sales

Wednesday May 25, 2022 10:09 am PDT by
Amazon is marking down a wide variety of 11-inch and 12.9-inch iPad Pro models this week, with prices starting as low as $749.00 for the 11-inch tablet. You'll find the full list of sales below, all of which can be found on Amazon. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make a purchase, we may receive a small payment, which helps us keep...
apple account card

Wallet App Now Supports Apple Account Cards on iOS 15.5

Wednesday May 25, 2022 5:01 pm PDT by
Apple appears to have recently updated the Wallet app to allow users to add an Apple Account Card, which displays the Apple credit balance associated with an Apple ID. If you receive an App Store or Apple Store gift card, for example, it is added to an Apple Account that was previously visible in the App Store and Apple Store apps. As of today, the Apple Account balance can also be added to...
iphone 13 pro max display bleen

iPhone 14 Max Reportedly Weeks Behind Schedule [Updated]

Thursday May 26, 2022 7:25 am PDT by
The iPhone 14 Max is currently behind schedule by around three weeks, according to Haitong International Securities analyst Jeff Pu. Yesterday, Nikkei Asia reported that at least one iPhone 14 model was three weeks behind schedule due to the impact of lockdowns on Apple's supply chains in China, but it was not clear which iPhone 14 model this related to. Now, Pu has clarified that the model...
iPhone 13 Always On Feature

iPhone 14 Pro Screen Refresh Rate Upgrade Could Allow for Always-On Display

Tuesday May 24, 2022 7:23 am PDT by
Last year's iPhone 13 Pro models were the first of Apple's smartphones to come with 120Hz ProMotion displays, and while the two iPhone 14 Pro models will continue to feature the technology, their screens could well boast expanded refresh rate variability this time round. To bring ProMotion displays to the ‌iPhone 13 Pro models‌, Apple adopted LTPO panel technology with variable refresh...
Apple Tap to Pay iPhone

Apple Stores Rolling Out iPhone-to-iPhone Contactless Payments Starting Today

Wednesday May 25, 2022 6:54 am PDT by
Apple in February unveiled a new "Tap to Pay on iPhone" feature that will allow compatible iPhones to accept payments via Apple Pay, contactless credit and debit cards, and other digital wallets, with no additional hardware required. Apple began testing the feature at its Apple Park Visitor Center earlier this month, and now Bloomberg's Mark Gurman has tweeted that the feature will begin...
apple tv 4k design green

Apple Releases tvOS 15.5.1 for Apple TV HD and Apple TV 4K

Wednesday May 25, 2022 9:42 am PDT by
Apple today released tvOS 15.5.1, a minor update to the tvOS operating system that first launched in September 2021. tvOS 15.5.1 comes about 10 days after the launch of tvOS 15.5. tvOS 15.5.1 can be downloaded over the air on the Apple TV through the Settings app by going to System > Software Update. ‌‌‌‌‌‌Apple TV‌‌‌‌‌‌ owners who have automatic software updates...