Meltdown and Spectre
ÆPIC Leak

SQUIP (PDF), AMD - Execution Unit Scheduler Contention Side-Channel Vulnerability on AMD Processors

GitHub - platomav/CPUMicrocodes Intel, AMD, VIA & Freescale CPU Microcode Repositories.
GitHub - intel/Intel-Linux-Processor-Microcode-Data-Files Intel Processor Microcode Package for Linux.

root/amd-ucode/README AMD microcode in linux-firmware package.

GitHub - speed47/spectre-meltdown-checker Reptar, Downfall, Zenbleed, ZombieLoad, RIDL, Fallout, Foreshadow, Spectre, Meltdown vulnerability/mitigation checker for Linux & BSD.

AMD Product Security:

• AMD - AMD-SB-7033 - AMD CPU Microcode Signature Verification Vulnerability

Tom's Hardware - Intel vs AMD Processor Security: Who Makes the Safest CPUs? By Lucian Armasu. Last updated November 10, 2019.
CSO Online - 37 hardware and firmware vulnerabilities: A guide to the threats Aug 11, 2022
gHacks Tech News - Security vulnerabilities found in Intel and AMD processors Aug 10, 2022. Mentions ÆPIC Leak and SQUIP.

superuser - How to find out the latest available microcode version for an AMD CPU?
Random Bits Of Computer Info - Zenbleed microcode update on AMD Ryzen 5 3600