MacRumors published a story that Apple has released macOS Big Sur 11.2.3 with a security fix for WebKit.

Apple Releases macOS Big Sur 11.2.3 With WebKit Security Fix

Apple today released macOS Big Sur 11.2.3, the fifth update to the ‌macOS Big Sur‌ operating system that launched in November. ‌macOS Big Sur‌ 11.2.3 comes two weeks after the release of macOS 11.2.2, a bug fix update. The new ‌‌‌‌‌‌macOS Big Sur‌‌‌‌‌ 11.2.3 update can be downloaded for free on all eligible Macs using the Software Update section of System Preferences. 

Apple Releases macOS Big Sur 11.2.3 With WebKit Security Fix