In affected versions of Octopus Server an Insecure Direct Object Reference vulnerability exists where it is possible for a user to download Project Exports from a Project they do not have permissions to access. This vulnerability only impacts projects within the same Space.
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 Server after version 2018.8.2 if the Octopus Server Web Request Proxy is configured with authentication, the password is shown in plaintext in the UI.