Starting in version 5.3.0, Kibana had a cross-site scripting (XSS) vulnerability in the Discover page that could allow an attacker to obtain sensitive information from or perform destructive actions on behalf of other Kibana users.
https://www.elastic.co/community/security
https://www.elastic.co/blog/kibana-5-4-1-and-5-3-3-released
https://discuss.elastic.co/t/elastic-stack-5-4-1-and-5-3-3-security-updates/87952