Apple has released macOS Big Sur 11.5.1 with security updates only a few days after macOS 11.5 dropped.
The new macOS update will automatically download and install for users who have that option enabled. Users can also navigate to System Preferences to initiate the update manually.
There was no beta period for this release, likely due to it containing minor security changes. The previous update, macOS 11.5, went through five beta iterations including a Release Candidate, with the latter issued on July 13.
At this time, it is unclear exactly what the new build offers, outside a maintenance and compatibility release. Given that macOS 11.5 was a maintenance release, and that macOS Monterey is currently being beta-tested, it seems unlikely that there will be major changes in the build.
Update: Apple confirms the update fixes a security vulnerability that may have been exploited in the wild.