ESXi : This host is potentially vulnerable to issues described in CVE-2018-3646

This is a very short post in reaction to those who asked me recently.

When you update to the latest ESXi builds you can see the warning message as depicted on the screenshot below.

Warning message in ESXi Client User Interface (HTML5)

This message just informs you about Intel CPU Vulnerability described in VMware Security Advisory 2018-0020 (VMSA-2018-0020).

You have three choices

• to eliminate the security vulnerability
• ignore potential security risk and dismiss the warning
• keep it as it is and ignore the warning in User Interface

Elimination of "L2 Terminal" security vulnerability is described in VMware KB 55806. It is configurable by ESXi advanced option VMkernel.Boot.hyperthreadingMitigation. If you set a value to TRUE or 1, ESXi will be protected.

The warning message suppression is configurable by another ESXi advanced option UserVars.SuppressHyperthreadWarning. A value TRUE or 1 will suppress the warning message.