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.