In affected versions of Octopus Server it was possible for a low privileged user to manipulate an API request to change the signing key expiration and revocation time frames via an API endpoint that had incorrect permission validation. It was not possible to expose the signing keys using this vulnerability.
In affected Microsoft Windows versions of Octopus Deploy, the server can be coerced into sending server-side requests that contain authentication material allowing a suitably positioned attacker to compromise the account running Octopus Server and potentially the host infrastructure itself.
In affected versions of Octopus Deploy users of certain browsers using AD to sign-in to Octopus Server were able to bypass authentication checks and be redirected to the configured redirect url without any validation.