Make no mistake, Sinkhole is a major security flaw. However, it’s not an exploit the vast majority of users need to worry about.
Sinkhole, which was discovered by researchers at IOActive, allows attackers to run code in System Management Mode.
'You basically have to throw your computer away': Researchers explain AMD 'Sinkclose' vulnerability, but do you need to worry?
Disclaimer:
Its called "sinkclose" by researchers and some media & "sinkhole" by some media
AMD has released a list of all affected processors
https://www.amd.com/en/resources/product-security/bulletin/amd-sb-7014.html
Via its security page
DEF CON Official Talk | AMD Sinkclose: Universal Ring-2 Privilege Escalation | Las Vegas, NV
https://ioactive.com/event/def-con-talk-amd-sinkclose-universal-ring-2-privilege-escalation/