When generating a user invitation code in Octopus Server, the validity of this code can be set for a specific number of users. It was possible to bypass this restriction of validity to create extra user accounts above the initial number of invited users.
In Octopus Deploy version 2018.5.1 to 2018.5.7, a user with Task View is able to view a password for a Service Fabric Cluster, when the Service Fabric Cluster target is configured in Azure Active Directory security mode and a deployment is executed with OctopusPrintVariables set to True. This is fixed in 2018.6.0.