https://wccftech.com/amd-zen-and-zen-2-cpus-vulnreable-to-meltdown-like-exploits-cyberattacks/

In October 2020, cybersecurity researchers Christof Fetzer and Saidgani Musaev of the Dresden Technology University ascertained a  Meltdown-Like vulnerability that affects both Zen+ and Zen 2 microarchitectures in AMD processors by producing illegal data sequences between both the processor and the microarchitectures.

The title of the process is "Transient Execution of Non-canonical Accesses". The cybersecurity team did not divulge the information in October to give AMD the proper time frame to investigate and create a mitigating solution.