In Kibana X-Pack security versions prior to 5.4.3 if a Kibana user opens a crafted Kibana URL the result could be a redirect to an improperly initialized Kibana login screen. If the user enters credentials on this screen, the credentials will appear in the URL bar. The credentials could then be viewed by untrusted parties or logged into the Kibana access logs.

Kibana versions prior to 5.6.1 had a cross-site scripting (XSS) vulnerability in Timelion that could allow an attacker to obtain sensitive information from or perform destructive actions on behalf of other Kibana users.