Overnight European time, Apple released a small but urgent update to macOS Sequoia, bringing it to version 15.0.1. Although there are no updates to Sonoma or Ventura, there are updated versions of Safari for both.

This Sequoia update is about 1.42 GB for Apple silicon Macs, and around 500 MB for Intel models. It doesn’t bring any firmware updates, but Safari is updated to version 18.0.1 (20619.1.26.31.7). While Apple has released security notes for the concomitant updates for iOS and iPadOS, there are none reported for macOS.

Although Apple remains tight-lipped about exactly what has been fixed in this update, it does admit to fixing a bug in Messages that could crash the app in unusual circumstances, and to improving “compatibility with third-party security software”. It’s assumed the latter refers to the network problems that have been widely reported.

Changes seen in bundled apps include a single build increment in Messages, and Passwords with a new version of 1.0.1. Apart from those and Safari, the only other bundled app to see any change is Photos, with a small build increment. This suggests that there are undisclosed improvements to the new Passwords app.

Significant changes seen in /System/Library include:

• Dock, small build increment
• CFNetwork and Network frameworks, build increments
• MobileSoftwareUpdate private framework, build increment
• Many Photo-related private frameworks, build increments
• SafariSafeBrowsing private framework, build increment
• Sharing private frameworks, build increments
• APFS remains unchanged at version 2313.1.2.

Note that there are no changes in any kernel extensions.

[Updated with further details at 0830 GMT 4 October 2024.]