Privilege escalation through the invitations service

Pivotal Apps Manager, included in Pivotal Application Service versions 2.3.x prior to 2.3.18, 2.4.x prior to 2.4.14, 2.5.x prior to 2.5.10, and 2.6.x prior to 2.6.5, contains an invitations microservice which allows users to invite others to their organizations. A remote authenticated user can gain additional privileges by inviting themselves to spaces that they should not have access to.