diff --git a/src/backend/core/api/viewsets.py b/src/backend/core/api/viewsets.py
index 5d9bd360c6..d93118cd13 100644
--- a/src/backend/core/api/viewsets.py
+++ b/src/backend/core/api/viewsets.py
@@ -2066,7 +2066,7 @@ def cors_proxy(self, request, *args, **kwargs):
         GET /api/v1.0/documents/<resource_id>/cors-proxy
         Act like a proxy to fetch external resources and bypass CORS restrictions.
         """
-        url = request.query_params.get("url")
+        url = request.query_params.get("url").strip()
         if not url:
             return drf.response.Response(
                 {"detail": "Missing 'url' query parameter"},