source: http://www.securityfocus.com/bid/50296/info

Splunk is prone to a cross-site scripting vulnerability because it fails to sufficiently sanitize user-supplied data.

An attacker may leverage this issue to execute arbitrary HTML and script code in an unsuspecting user's browser in the context of the affected site. This may allow the attacker to steal cookie-based authentication credentials and launch other attacks.

Splunk versions 4.2.2 and prior are vulnerable. 

http://www.example.com/en-US/prototype/segmentation_performance?lines=2&depth=2&segment=%3Cscript%3Ealert%281%29%3B%3C%2Fscript%3E&element=aaa&attribute=aaa&segmentation=flattened