We have found a Vm instance with full access to all Cloud APIs that is using the default service account. To support principle of least privileges and prevent potential privilege escalation it is recommended that instances are not assigned to default service account Compute Engine default service account with Scope Allow full access to all Cloud APIs.
Recommended Mitigation
Create a new service account and assign only the permissions needed by your instance and ensure that the instance is not configured to allow 'cloud-platform' scope.