https://www.gamespot.com/articles/psa-the-spectre-and-meltdown-cpu-vulnerabilities-a/1100-6456619/

There is a lot of of hoopla surrounding Spectre and Meltdown, the names given to vulnerabilities that affect practically every processor produced in the past two decades. Without taking a deep dive into the technical details, the short of it is that they could allow an attacker to pluck what was previously considered protected data from your CPU’s cache, including passwords, encryption keys, and other sensitive information.