The Monitoring Console app configured in Distributed mode allows for a Reflected XSS in a query parameter in Splunk Enterprise versions before 8.1.4. The Monitoring Console app is a bundled app included in Splunk Enterprise, not for download on SplunkBase, and not installed on Splunk Cloud Platform instances. Note that the Cloud Monitoring Console is not impacted.
Splunk before 5.0.4 lacks X-Frame-Options which can allow Clickjacking
Splunk 5.0.3 has an Unquoted Service Path in Windows for Universal Forwarder which can allow an attacker to escalate privileges