In Splunk Enterprise versions below 8.2.9 and 8.1.12, the way that the rex search command handles field names lets an attacker bypass SPL safeguards for risky commands https://docs.splunk.com/Documentation/SplunkCloud/latest/Security/SPLsafeguards . The vulnerability requires the attacker to phish the victim by tricking them into initiating a request within their browser. The attacker cannot exploit the vulnerability at will.