PortSmash side-channel flaw that could be exploited with a timing attack to steal information from other processes running in the same CPU core with SMT/hyper-threading enabled. Experts successfully tested flaw against Intel Skylake and KabyLake processors, but they expect it works also on AMD Ryzen processors. Experts also published a proof-of-concept exploit that targets OpenSSL, maintainers of the library addressed the flaw with the release of the OpenSSL 1.1.1.”]
Source: https://securityaffairs.co/wordpress/77671/hacking/portsmash-flaw.html