Four new vulnerabilities have been discovered in Intel processors that can be exploited via speculative execution side-channel attacks called RIDL, Fallout, and ZombieLoad. These vulnerabilities allow attackers to steal passwords, cryptographic keys, or any other type of data to be loaded or stored in the memory of the CPU buffers. The current solutions are mitigations only and do not completely fix the vulnerabilities. To fully resolve these vulnerabilities, all vendors state that you would need to disable hyper-threading, which would have a performance impact on your computer.
Source: https://www.bleepingcomputer.com/news/security/list-of-mds-speculative-execution-vulnerability-advisories-and-updates/