Apple's latest Background Security Improvement targets a WebKit flaw

A Background Security Improvement in iOS 26.3.1 fixes a WebKit issue in Safari that could break one of the web's most important safety rules.

What’s the new 'Background Security' on the iPhone? What we know.

Apple's new Background Security Improvements operate between software updates, providing "lightweight security releases." ...

iOS 26.3.1 (a) is Out: The “Silent” Security Patch You Shouldn’t Ignore

OS 26.3.1(a) arrives as a background security update with a WebKit navigation API input-validation fix, with no new features ...
TidBITS

Apple Relaunches Background Security Improvements with WebKit Patch

Remember Rapid Security Responses? Apple renamed and relaunched them as Background Security Improvements, and the first one patches a WebKit flaw in iOS, iPadOS, and macOS 26.3.1. Here's what you need ...