Permissions Validation Failure in the ‘sendemail’ REST API Endpoint in Splunk Enterprise

In Splunk Enterprise versions below 8.1.13, 8.2.10, and 9.0.4, the ‘sendemail’ REST API endpoint lets any authenticated user send an email as the Splunk instance. The endpoint is now restricted to the ‘splunk-system-user’ account on the local instance.