In Splunk Enterprise versions below 8.1.13, 8.2.10, and 9.0.4, a cross-site request forgery in the Splunk Secure Gateway (SSG) app in the ‘kvstore_client’ REST endpoint lets a potential attacker update SSG KV store collections using an HTTP GET request.
https://research.splunk.com/application/4742d5f7-ce00-45ce-9c79-5e98b43b4410/