diff --git a/backend/open_webui/utils/misc.py b/backend/open_webui/utils/misc.py
index b8336e8fe7..e9cb78dc75 100644
--- a/backend/open_webui/utils/misc.py
+++ b/backend/open_webui/utils/misc.py
@@ -711,7 +711,7 @@ def sanitize_data_for_db(obj):
     # json.dumps is implemented in C and much faster than a Python-level
     # recursive walk over every leaf string.
     try:
-        if '\x00' not in json.dumps(obj, ensure_ascii=False):
+        if '\\u0000' not in json.dumps(obj, ensure_ascii=False):
             return obj
     except (TypeError, ValueError):
         pass