In affected versions of Octopus Server it is possible for a session token to be valid indefinitely due to improper validation of the session token parameters.
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.
An issue was discovered in Octopus Deploy 3.4. A deployment target can be configured with an Account or Certificate that is outside the scope of the deployment target. An authorised user can potentially use a certificate that they are not in scope to use. An authorised user is also able to obtain certificate metadata by associating a certificate with certain resources that should fail scope validation.