An error was found in the permission model used by X-Pack Alerting 5.0.0 to 5.6.0 whereby users mapped to certain built-in roles could create a watch that results in that user gaining elevated privileges.

An error was found in the X-Pack Security 5.3.0 to 5.5.2 privilege enforcement. If a user has either 'delete' or 'index' permissions on an index in a cluster, they may be able to issue both delete and index requests against that index.