In OpenStack Glance through 32.0.0, the /v2/tasks API accepts type=import tasks that bypass importfilteringopts, allowing an admin to fetch internal URLs from the Glance service network (aka SSRF), as long as https:// or http:// is used. This API has been available only to admins since Xena, and it has been deprecated for several releases.
The API before 2.1 in OpenStack Image Registry and Delivery Service (Glance) makes it easier for local users to inject images into arbitrary tenants by adding the tenant as a member of the image.