Apple has released an update for Safari 14.1.2 that should be installed using the Mac App Store on MacOS Catalina and MacOS Mojave.
This update contains security fixes that should be installed as soon as possible.
Users running MacOS Big Sur do not need to install this update.
Important links for MacOS Catalina and MacOS Mojave users:
How to update Safari
Safari 14.1.2 Release Notes