Catalina 10.15.5 Supplemental Update

Apple has released a Supplemental Update to the macOS Catalina 1015.5. This update is concerned primarily with Security fixes. Apple describes it like this:

According to the security notes for the update, it addresses a security flaw that could allow an application to execute arbitrary code with kernel privileges.

I have installed this update and all seems to be OK. However, YMMV with your Mac system and setup. You can download the update from the Mac App Store. It takes about 15 minutes to install. By the way, Apple released security updates for its other operating systems as well.