The vulnerability is found in a range of AMD chipsets. It affects everything from modern Ryzen processors to chips stretching all the way back at least as far as the AMD Athlon X4 from 2013 ...
New motherboards supporting AMD's X870 and X870E chipset are now available, launching first on Newegg. All boards support the new AMD Ryzen 9000 Series desktop processors with the AM5 socket.