In Splunk Enterprise versions below 9.2.2, 9.1.5, and 9.0.10 and Splunk Cloud Platform versions below 9.1.2312.109 and 9.1.2308.207, an authenticated user could create an external lookup that calls a legacy internal function. The authenticated user could use this internal function to insert code into the Splunk platform installation directory. From there, the user could execute arbitrary code on the Splunk platform Instance.
CWE-75 Failure to Sanitize Special Elements into a Different Plane (Special Element Injection)