In Splunk Enterprise versions lower than 9.0.6 and 8.2.12, a malicious actor can send a malformed security assertion markup language (SAML) request to the `/saml/acs` REST endpoint which can cause a denial of service through a crash or hang of the Splunk daemon.
https://research.splunk.com/application/8e8a86d5-f323-4567-95be-8e817e2baee6/