ESXI-70-000032 - The ESXi host must prohibit the reuse of passwords within five iterations.
If a user or root used the same password continuously or was allowed to change it back shortly after being forced to change it to something else, it would provide a potential intruder with the opportunity to keep guessing at one user's password until it was guessed correctly.
From the vSphere Client, go to Hosts and Clusters. Select the ESXi Host >> Configure >> System >> Advanced System Settings. Click 'Edit'. Select the 'Security.PasswordHistory' value and configure it to '5'. or From a PowerCLI command prompt while connected to the ESXi host, run the following command: Get-VMHost | Get-AdvancedSetting -Name Security.PasswordHistory | Set-AdvancedSetting -Value 5