https://googleprojectzero.blogspot.jp/2018/01/reading-privileged-memory-with-side.html

Variant 1: bounds check bypass (CVE-2017-5753)
Variant 2: branch target injection (CVE-2017-5715)
Variant 3: rogue data cache load (CVE-2017-5754)

上二つがSpectre
一番下がMeltdown

https://www.amd.com/en/corporate/speculative-execution

そしてAMDの見解だとパッチが必要なのは一番上だけ