With X-Pack installed, Kibana versions 5.0.0 and 5.0.1 were not properly authenticating requests to advanced settings and the short URL service, any authenticated user could make requests to those services regardless of their own permissions.
Kibana versions before 4.6.3 and 5.0.1 have an open redirect vulnerability that would enable an attacker to craft a link in the Kibana domain that redirects to an arbitrary website.