An issue was discovered in OpenStack Keystone before 15.0.1, and 16.0.0. Any user authenticated within a limited scope (trust/oauth/application credential) can create an EC2 credential with an escalated permission, such as obtaining admin while the user is on a limited viewer role. This potentially allows a malicious user to act as the admin on a project another user has the admin role on, which can effectively grant that user global admin privileges.