In Splunk Enterprise versions below 10.4.2, 10.2.6, 10.0.9, and 9.4.14, a user who does not hold the "admin" or "power" Splunk roles could perform Remote Code Execution (RCE) by submitting crafted Splunk Web Manager Configuration content. The user could then access all relevant data and affect system integrity and availability. The vulnerability is possible because Splunk Web evaluates manager Extensible Markup Language expressions without sufficient input restrictions, and the associated configuration route does not require the capability expected for manager configuration changes. For more information see About configuration files (https://help.splunk.com/en/data-management/splunk-enterprise-admin-manual/10.4/administer-splunk-enterprise-with-configuration-files/about-configuration-files) in the Splunk documentation.
The vulnerability affects instances with Splunk Web turned on. Turning Splunk Web off is a possible workaround. See Disable unnecessary Splunk Enterprise components and the web.conf configuration specification file for more information on turning off Splunk Web.
Upgrade Splunk Enterprise to versions 10.4.2, 10.2.6, 10.0.9, and 9.4.14, or higher.