CVE-2026-119675: mongorestore may bypass collection guards through a system.buckets prefix

MongoDB Database Tools mongorestore inconsistently handles the system.buckets. prefix when validating collection names in an untrusted dump. A specially crafted collection name can bypass special-collection guards and operator namespace filters, causing a restore to create an unauthorized user-chosen database account, including an account with the root role. Exploitation requires an operator to restore unauthorized user-controlled data using credentials with sufficient user-management privileges on the destination deployment. Excluding the admin namespace alone does not prevent this behavior. This issue affects MongoDB Database Tools versions 100.4.0 through versions before 100.20.1.