How to fix error: CVE-2018-3646 on VMWare ESXi

  • Connect to the vCenter Server using either the vSphere Web or vSphere Client.
  • Select an ESXi host in the inventory.
  • Click the Manage (5.5/6.0) or Configure (6.5/6.7) tab.
  • Click the Settings sub-tab.
  • Under the System heading, click Advanced System Settings.
  • Click in the Filter box and search VMkernel.Boot.hyperthreadingMitigation
  • Select the setting by name and click the Edit pencil icon.
  • Change the configuration option to true (default: false).
  • Click OK.
  • Reboot the ESXi host for the configuration change to go into effect.


Solve the Issue from CLI:
  • Connect to the host using SSH
  • Check the current runtime value of the HTAware Mitigation Setting by running: esxcli system settings kernel list -o hyperthreadingMitigation
  • Enable HT Aware Mitigation by running: esxcli system settings kernel set -s hyperthreadingMitigation -v TRUE
  • Reboot the ESXi Host.

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