Macos Big Sur 11.5.1 (20g80) Apr 2026
: Resolved an issue where smart cards might not work correctly when logging into M1-based Macs. Installation & Compatibility
: This was a "surprise" security patch released just five days after version 11.5.
: Addresses a serious vulnerability in the IOMobileFrameBuffer .
: An application could potentially execute arbitrary code with kernel privileges.
: Available for all Macs compatible with Big Sur, including MacBook (2015+), MacBook Air (2013+), and iMac (2014+).
: Fixed an issue where the play count or last played date might not update in the library.
: Users typically install this by going to System Preferences > Software Update .
: Resolved an issue where smart cards might not work correctly when logging into M1-based Macs. Installation & Compatibility
: This was a "surprise" security patch released just five days after version 11.5.
: Addresses a serious vulnerability in the IOMobileFrameBuffer .
: An application could potentially execute arbitrary code with kernel privileges.
: Available for all Macs compatible with Big Sur, including MacBook (2015+), MacBook Air (2013+), and iMac (2014+).
: Fixed an issue where the play count or last played date might not update in the library.
: Users typically install this by going to System Preferences > Software Update .