For those that are not following IT security that closely: people involved with Spectre, Meltdown and Foreshadow have cooperated and done a „systematic Evaluation of Transient Execution Attacks and Defenses“. In the course they have discovered seven (!) new Spectre/Meltdown-style attacks. They tested their findings on Intel, AMD and ARM CPUs: „we can still mount transient execution attacks that are supposed to be mitigated by rolled out patches.“