All the major Intel vulnerabilities
RIDL is part of a class of vulnerabilities impacting modern processors that are named Microarchitectural Data Sampling attacks, or MDS attacks. These attacks target a CPU’s microarchitectural data structures, such as the load, store, and line fill buffer caches.
More specifically, RIDL exploits a hardware design flaw in the line buffer cache to extract secret data from a CPU’s sensitive areas. It is similar to ZombieLoad, however, different, and was discovered by a different set of academics.