Apache CloudStack 4.1 to 4.8.1.0 and 4.9.0.0 contain an API call designed to allow a user to register for the developer API. If a malicious user is able to determine the ID of another (non-"root") CloudStack user, the malicious user may be able to reset the API keys for the other user, in turn accessing their account and resources.
Apache CloudStack before 4.5.2 does not properly preserve VNC passwords when migrating KVM virtual machines, which allows remote attackers to gain access by connecting to the VNC server.