Israeli security firm CTS Labs claims to have discovered the flaws when it analyzed a modern AMD CPU and spotted what appeared to be the backdoor code it previously discovered in old ASMedia firmware. This sparked a more in-depth investigation that later unearthed 13 security bugs. The flaws are organized across four vulnerability classes named FalloutKey, MasterKey, and Chimera. AMD hasn’t even confirmed that the report contains valid findings. The affected AMD CPUs are deployed in desktops, notebooks, smartphones, and servers alike.
Source: https://www.bleepingcomputer.com/news/security/amd-investigating-ryzenfall-masterkey-fallout-and-chimera-cpu-vulnerabilities/