Intel addressed 14 security vulnerabilities during the December 2019 Patch Tuesday. Seven of them are high and medium severity security flaws impacting multiple platforms including Windows and Linux. Intel also addressed a newly discovered attack dubbed by researchers behind it Plundervolt targeting Intel Software Guard eXtensions (SGX) set of security-related instruction codes within modern Intel CPUs. Intel recommends users of the Intel Processors listed above to install the latest BIOS version provided by their system’s manufacturer to address this issue as soon as possible.
Source: https://www.bleepingcomputer.com/news/security/intel-patches-plundervolt-high-severity-issues-in-platform-update/

