Updated amd64-microcode for EPYC processors appears available for several distributions which has mitigations available. I went ahead and proactively grabbed the microcode update from Debian unstable (not the best practice) and applied it without issue to my Bullseye/EPYC.

This isn’t exactly condoned as it’s not officially a backport, but I’ll take my chances as this is pretty critical.

Date of the updated microcode should be July 19th.