Macos Big Sur 11.5.1 (20g80) -

Released on July 26, 2021, is a maintenance update primarily focused on a critical security patch. Key Update Details

: Apple stated they were aware of reports that this issue may have been actively exploited in the wild.

: This security fix was released simultaneously with iOS 14.7.1 and iPadOS 14.7.1 to address the same vulnerability. macOS 11.5.1 - Apple Wiki | Fandom macOS Big Sur 11.5.1 (20G80)

While 11.5.1 was security-focused, it carries over the bug fixes introduced in 11.5 (20G71), including:

: This was a "surprise" security patch released just five days after version 11.5. Released on July 26, 2021, is a maintenance

: An application could potentially execute arbitrary code with kernel privileges.

: Despite being a single-patch update, the download size was approximately 2.2 GB for Intel Macs and over 3.1 GB for M1 Macs . Improvements from the 11.5 Branch macOS 11

: Addresses a serious vulnerability in the IOMobileFrameBuffer .