The new Intel microcode firmware security update mitigates the L1 Terminal Fault (L1TF) vulnerability documented as CVE-2018-3646, which could allow an attacker in a guest virtual machine to expose sensitive information from either the host operating system or other guests. It also fixes the well known Spectre Variant 4 security vulnerability (CVE-2018-3639) that could allow an attacker to expose sensitive information, including kernel memory via a side-channel attack, and another side-channel attack known as Rogue System Register Read (RSRE) and documented as (CVE-2018-3640).