Meanwhile, as a footnote: "The vulnerability affects all of AMD's existing Ryzen processors featuring Zen 1/2/3 microarchitectures. To exploit the weakness and get access to data processed by the same CPU core, perpetrators need to run malicious code on that CPU core first, which is not particularly easy. "
AMD gets what seems to be a worse problem than the one Intel had when the old "disable hyperthreading" Foreshadow bug came out. That one is long fixed, but this new AMD one presents every bit as consequential of a risk (really pretty close to negligible, but Intel's was moreso).
And the only fix is to disable SMT, but AMD just recommends you ignore the bug and do best practices because security exploits are hard to do.