Label Studio contains a broken access control vulnerability in its AnnotationAPI endpoint (label_studio/tasks/api.py) where the queryset is declared as Annotation.objects.all() with no organization-scoped filtering. The permission system only checks if a user is authenticated, bypassing any object-level organization boundary checks. Since annotation identifiers are sequential integers, an authenticated user from one organization can enumerate and access, modify, or delete annotations belonging to other organizations on the same instance. The same unscoped queryset vulnerability also exists in AnnotationConvertAPI in the same file. A sibling task endpoint correctly scopes queries by organization, demonstrating that the fix pattern is known but was not applied here. This represents a significant multi-tenant isolation failure in Label Studio deployments shared across organizations.