diff --git a/backend/open_webui/retrieval/utils.py b/backend/open_webui/retrieval/utils.py
index 8f5c080298..7017da7c2e 100644
--- a/backend/open_webui/retrieval/utils.py
+++ b/backend/open_webui/retrieval/utils.py
@@ -120,6 +120,9 @@ def _extract_text_from_binary_response(
     if not filename or '.' not in filename:
         ext = mimetypes.guess_extension(content_type) or ''
         filename = f'download{ext}'
+    elif not mimetypes.guess_type(filename)[0] and content_type != 'application/octet-stream':
+        # The dot in names like arXiv's 1706.03762 is not an extension.
+        filename += mimetypes.guess_extension(content_type) or ''
 
     suffix = '.' + filename.split('.')[-1].lower() if '.' in filename else ''