VMware Aria Operations 8.12.1 HF3 is available, you can find it here! This is the third Hot Fix for 8.12.x releases, the others are listed here:
Aria Operations 8.12.1 HF2, this requires an upgrade to 8.12.1 before applying, details can be found here.
I'm using Aria Suite Lifecycle to manage my Aria environment, I've logged in, gone to Lifecycle Operations, Settings, Binary Mapping, Patch Binaries.
Click CHECK PATCHES ONLINE.
You can view progress via Requests. Once done you'll see the new HF3.
Once discovered, you can download it.
One downloaded, you can apply it by going to Environments - your environment - Operations tab - three dots - Patches - Install Patch.
Once done, go back into Patches - History to confirm application.
And...you're done!