diff --git a/backend/open_webui/functions.py b/backend/open_webui/functions.py
index 7b102d5e56..d38d6b8367 100644
--- a/backend/open_webui/functions.py
+++ b/backend/open_webui/functions.py
@@ -36,7 +36,8 @@ from open_webui.utils.plugin import (
 )
 from open_webui.utils.access_control import check_base_model_access
 
-from open_webui.env import GLOBAL_LOG_LEVEL
+from open_webui.env import GLOBAL_LOG_LEVEL, BYPASS_MODEL_ACCESS_CONTROL
+from open_webui.config import BYPASS_ADMIN_ACCESS_CONTROL
 
 from open_webui.utils.misc import (
     add_or_update_system_message,
@@ -260,7 +261,12 @@ async def generate_function_chat_completion(request, form_data, user, models: di
     if model_info:
         if model_info.base_model_id:
             form_data['model'] = model_info.base_model_id
-            await check_base_model_access(user, model_info.base_model_id)
+            await check_base_model_access(
+                user,
+                model_info.base_model_id,
+                bypass_filter=BYPASS_MODEL_ACCESS_CONTROL
+                or (isinstance(user, UserModel) and user.role == 'admin' and BYPASS_ADMIN_ACCESS_CONTROL),
+            )
 
         params = model_info.params.model_dump()
 
diff --git a/backend/open_webui/routers/models.py b/backend/open_webui/routers/models.py
index 193e58530a..fe7cccf3ce 100644
--- a/backend/open_webui/routers/models.py
+++ b/backend/open_webui/routers/models.py
@@ -332,6 +332,11 @@ async def import_models(
             return True
         else:
             raise HTTPException(status_code=400, detail='Invalid JSON format')
+    except HTTPException:
+        # Preserve intentional HTTP status codes (e.g. 403 from base-model access
+        # checks, 400 from validation). The broad handler below otherwise masks
+        # them as 500, which misreports authz failures as server errors.
+        raise
     except Exception as e:
         log.exception(e)
         raise HTTPException(status_code=500, detail=str(e))