diff --git a/api/db/services/document_service.py b/api/db/services/document_service.py
index ed6220aed..5e1f5b0e0 100644
--- a/api/db/services/document_service.py
+++ b/api/db/services/document_service.py
@@ -317,7 +317,7 @@ class DocumentService(CommonService):
     @classmethod
     @DB.connection_context()
     def get_thumbnails(cls, docids):
-        fields = [cls.model.id, cls.model.thumbnail]
+        fields = [cls.model.id, cls.model.kb_id, cls.model.thumbnail]
         return list(cls.model.select(
             *fields).where(cls.model.id.in_(docids)).dicts())