diff --git a/orbit/radius.py b/orbit/radius.py
index 33e3d851..785c8428 100644
--- a/orbit/radius.py
+++ b/orbit/radius.py
@@ -474,6 +474,8 @@ def form_respond():
 
 
 def handle_cgit(rocket):
+    if not rocket.session:
+        return rocket.raw_respond(HTTPStatus.UNAUTHORIZED)
     cgit_env = os.environ.copy()
     cgit_env['PATH_INFO'] = rocket.path_info.removeprefix('/cgit')
     cgit_env['QUERY_STRING'] = rocket.env.get('QUERY_STRING', '')