Update to macOS Big Sur 11.5.1 to protect your Mac against a vulnerability exploited in the wild

Get the latest Apple security protections by updating your Mac computer to the new macOS Big Sur 11.5.1 software through the Software Update mechanism in System Preferences.


  • macOS Big Sur 11.5.1 is available now for all compatible Macs
  • It includes a fix for a vulnerability in IOMobileFrameBuffer
  • Apple says the issue may have been exploited in the wild


The icon representing the macOS Big Sur installer

Apple also launched iOS and iPadOS 14.7.1 alongside macOS Big Sur 11.5.1, indicating the patched vulnerability could easily affect iPhones and iPads as well rather than just Macs.

What security issues does macOS Big Sur 11.5.1 fix?

A support document on the Apple website provides additional insight into the security content of the new macOS Big Sur 11.5.1 software. The bug-fix update, Apple clarifies, patches a vulnerability allowing an app to execute arbitrary code with kernel privileges.

Apple is also aware of a report that this issue may have been actively exploited.

The discovery of the vulnerability is credited to an anonymous researcher, another clue that this is a fix for a major zero-day vulnerability rather than just another quick bug fix. The document says the memory corruption issue was addressed with improved memory handling.

It’s unclear whether this fixes the many security issues with Apple’s iMessage protocol, which has been blamed for being a major attack vector for NSO’s Pegasus spyware. From what’s known so far, Pegasus installs itself onto an unsuspecting device via a specially encoded iMessage that gets delivered silently and requires no action on the user’s part.

How to install the macOS Big Sur 11.5.1 update

You install macOS Big Sur 11.5.1 just like you would any other modern macOS update.

Firstly, click the Apple menu and choose the option labeled “System Preferences”. In the System Preferences window, click the icon Software Update. If an update is found, you’ll see a message. To download and install the update, hit the option “Update Now” or “Upgrade Now”.

Follow onscreen instructions to finish installing the update.

For more information about Apple’s security updates, visit this dedicated page.