Your iPhone may have been holding onto Signal messages long after you deleted them, and the FBI actually used that to pull message previews from a suspect’s device during a court case. Apple just patched the flaw, but the story behind it is worth understanding.
Details about the vulnerability surfaced through recent court testimony. The FBI accessed an internal notification database on an iPhone connected to an active case.
The person involved had already deleted the Signal app and had disappearing messages turned on, which should have wiped everything clean. It did not.
The catch was that the iPhone had been set up to show Signal message content directly on the Lock Screen.
When you enable that feature, your phone saves the actual text of those notifications to a local database.
Even after the app was gone, the database continued to store that content, and law enforcement was able to access it.
Also: Why millions of your favorite apps might suddenly stop working when iOS 27 hits this fall
What Was Actually Going Wrong Inside iOS
The issue came down to how iOS handled notification logging. Notifications that should have been cleared from the system were not being properly removed.
Apple described the fix as improved data redaction, meaning the logging process will no longer retain sensitive content as it did before.
It is a subtle but important distinction. The problem was not that Signal failed to encrypt your messages.
The problem was that iOS was quietly writing notification previews to a database and not cleaning them up the way it was supposed to.
Which Update Actually Fixes It
Apple rolled out the patch today. If your iPhone or iPad is running iOS 26 or iPadOS 26, you want iOS 26.4.2 or iPadOS 26.4.2.
If you are still on iOS 18 or iPadOS 18, the fix is in iOS 18.7.8 or iPadOS 18.7.8. You can grab either one by heading to Settings, tapping General, then Software Update.
If you have message previews turned on in any app, your phone stores that content locally for display in notifications.
Most people never think about that. For everyday use, it is a convenience feature, but as this case showed, it can create a paper trail in places you would not expect to find one. Worth reviewing those notification settings regardless of whether you use Signal.
