macOS and iOS 26.3.1(a) released – as “Background Security Improvement” | News

If security gaps come to light, you need to act quickly – especially if they are already being exploited. Therefore, Apple has previously looked for ways to quickly release updates without releasing a full update. For this reason, the company introduced “Rapid Security Responses” with iOS 16.4.1 and macOS 13.3.1, which were only used once and caused problems at the time.

With macOS 26 and iOS 26, Apple introduced the successor: “Background Security Improvements”. Like its predecessor, these are intended to enable the group to react quickly to security threats and distribute updates. During the beta phase of macOS 26.3 and iOS 26.3, Apple already tested the “Background Security Improvements” – but never with end customers.

In use for the first time
This evening Apple is distributing an update using “Background Security Improvements” for the first time. A vulnerability has appeared in WebKit that allows the “Same Origin Policy” security policy to be circumvented using a specially prepared website.

The security update via “Background Security Improvements” is available for macOS 26.3.1, iOS 26.3.1 and iPadOS 26.3.1. Since the new MacBook Neo was already delivered with macOS 26.3.2, Apple is releasing a separate update here. After installation, the new versions appear as 26.3.1(a) or 26.3.2(a).

Updates for older system versions have not yet been released. It is possible that the current vulnerability only exists on macOS 26, iOS 26 or iPadOS 26.

Compatibility problems possible
Apple points out in the description that in rare cases unspecified compatibility problems may occur. Fortunately, the “Background Security Improvements” can be easily uninstalled. To do this, open the system settings on your Mac, iPhone or iPad and select “Privacy & Security”. Here you will find an option to stop the updates completely or to undo individual updates that have been installed.