In Splunk Enterprise versions below 9.3.1, 9.2.3, and 9.1.6, the software potentially exposes sensitive HTTP parameters to the `_internal` index. This exposure could happen if you configure the Splunk Enterprise `REST_Calls` log channel at the DEBUG logging level.
https://research.splunk.com/application/93dc7182-c5da-4085-82ec-401abf33d623/