A flaw was found in Red Hat Quay's repository-level mirror configuration
feature. The POST and PUT handlers in endpoints/api/mirror.py accept an
external_reference parameter without SSRF validation, unlike the
organization-level mirror handlers which apply validate_external_registry_url().
A repository administrator can supply a crafted hostname that causes the Quay
mirror worker to make requests via Skopeo to internal network services, cloud
metadata endpoints, or other resources not intended to be reachable from the
Quay application.
Credits
This issue was discovered by Martin Brodeur and Shaon Hossain (Red Hat).
