An update to fix the issue of 'encrypted chat history being intercepted via iPhone notifications' will be released as iOS 26.4.2.

On April 22, 2026, Apple announced security updates for iOS 26.4.2 and iPadOS 26.4.2. These updates were released in response to

https://support.apple.com/ja-jp/127002

The incident began with reports that the FBI had recovered the contents of Signal messages received on the defendant's iPhone. Signal, an encrypted messaging app, is characterized by its end-to-end encryption, ensuring that message content is not leaked to outsiders. However, the report attracted attention because the message content was recovered even though the Signal app had been deleted from the iPhone.

FBI successfully recovers deleted messages from encrypted messaging app 'Signal,' revealing they were still present in iPhone notification databases - GIGAZINE

iOS 26.4.2 and iPadOS 26.4.2 fix a bug ( CVE-2026-28950 ) related to the notification service that was likely used to restore Signal messages.

The following devices are included: iPhone 11 and later, iPad Pro 12.9-inch (3rd generation and later), iPad Pro 11-inch (1st generation and later), iPad Air (3rd generation and later), iPad (8th generation and later), and iPad mini (5th generation and later).

This bug caused notifications that should have been marked for deletion to unexpectedly remain on the device. According to Apple, they were able to fix the bug by improving data masking.

Regarding this, Signal posted: 'We are very pleased that Apple has issued a patch and security advisory. This is in response to reports that the FBI recovered deleted Signal messages via the iPhone's notification database. The message content was recovered via notifications even though the app had been deleted. Apple's advisory confirms that the bug that made this possible has been fixed in the latest iOS. This fix means that no special action is required to protect Signal users on iOS. Simply install the patch and all mistakenly saved notifications will be deleted, and future notifications for the deleted app will no longer be retained. We appreciate Apple's swift response and their understanding of the seriousness of this type of issue. Protecting the fundamental human right of private communication requires a community-wide effort.'

We are very happy that today Apple issued a patch and a security advisory. This comes following @404mediaco reporting that the FBI accessed Signal message notification content via iOS despite the app being deleted.

Apple’s advisory confirmed that the bugs that allowed this to…

— Signal (@signalapp) April 22, 2026

iOS 26.4.2 and iPadOS 26.4.2 are already available for download. You can update immediately by going to the Settings app on your iPhone or iPad, tapping General, then Software Update, and then tapping Update Now.