Looks like a pretty nasty vulnerability is affecting Intel processors, but not AMD.
From Intel – First identified by Intel’s internal researchers and partners, and independently reported to Intel by external researchers, MDS is a sub-class of previously disclosed speculative execution side channel vulnerabilities and is comprised of four related techniques. Under certain conditions, MDS provides a program the potential means to read data that program otherwise would not be able to see.
For more, visit this Intel page.
From AMD – Based on our analysis and discussions with the researchers, we believe our products are not susceptible to ‘Fallout’ or ‘RIDL’ because of the hardware protection checks in our architecture. We have not been able to demonstrate these exploits on AMD products and are unaware of others having done so.
For more, visit this AMD page.