An issue was discovered in OpenStack Keystone before 15.0.1, and 16.0.0. Any authenticated user can create an EC2 credential for themselves for a project that they have a specified role on, and then perform an update to the credential user and project, allowing them to masquerade as another user.
The information has been provided by Kay
The original article can be found at:https://security.openstack.org/ossa/OSSA-2020-004.html
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.
OpenStack Keystone before 15.0.1
OpenStack Keystone before 16.0.0