Macos Big Sur 11.5.1 (20g80) Apr 2026

: Available for all Macs compatible with Big Sur, including MacBook (2015+), MacBook Air (2013+), and iMac (2014+).

: Resolved an issue where smart cards might not work correctly when logging into M1-based Macs. Installation & Compatibility macOS Big Sur 11.5.1 (20G80)

: Fixed an issue where the play count or last played date might not update in the library. : Available for all Macs compatible with Big

: This was a "surprise" security patch released just five days after version 11.5. including MacBook (2015+)

: Addresses a serious vulnerability in the IOMobileFrameBuffer .

: 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

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