Apple has released its first Background Security Improvement (BSI) update, marking a shift away from the rapid security updates it used to roll out a few years ago. Apple says the new update system is designed to deliver security improvements between software updates and is available only for the latest versions of iOS, iPadOS and macOS.
Why did Apple release a Background Security Improvement update?
Apple says that the Background Security Improvements are designed to deliver ‘lightweight security releases’ for components like the Safari browser, WebKit framework stack and other system libraries, which can benefit from smaller, ongoing security patches between software updates.
The tech giant released its first-ever BSI update on 17 March for iOS 26.3.1, iPadOS 26.3.1, macOS 26.3.1, and macOS 26.3.2. Apple says that the first update was pushed out to address a specific vulnerability within WebKit, the browser engine that powers Safari and other iOS web apps.
Apple says the problem was due to a cross-origin issue in the Navigation API, which was assigned CVE-2026-20643. The issue could allow maliciously crafted web content to bypass the Same Origin Policy, the company said.
The company noted that the issue was successfully addressed with improved input validation.
The first update will appear with an ‘a ’ suffix like iOS 26.3.1 (a), iPadOS 26.3.1 (a), macOS 26.3.1 (a), and macOS 26.3.2 (a).
“Background Security Improvements deliver additional security protections between software updates,” the company said in a blog post.
How to install the Apple BSI update?
The BSI updates are set to install automatically in the background by default. Since these are lightweight updates, they typically require a phone restart rather than a full reboot, which is reserved for longer software updates.
Users can disable automatic downloading of BSI updates in Settings on their iPhone or Mac. Here are the detailed settings:
iPhone: Settings > Privacy & Security > Background Security Improvements
Mac: Apple Menu > System Settings > Privacy & Security > Background Security Improvements.
The company recommends keeping the “Automatically Install” setting turned on. However, if users turn off this setting, they will not receive the update until it comes included in a subsequent software update.
Apple says that in rare instances of compatibility issues, it may temporarily remove BSI updates and then add an improved version with the next software update.
