diff --git a/changelog.d/10079.bugfix b/changelog.d/10079.bugfix
new file mode 100644
index 000000000..2b93c4534
--- /dev/null
+++ b/changelog.d/10079.bugfix
@@ -0,0 +1 @@
+Fix a bug introduced in v1.35.0rc1 when calling the spaces summary API via a GET request.
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index 9d50b05d0..40eab4554 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -1398,7 +1398,7 @@ class FederationSpaceSummaryServlet(BaseFederationServlet):
                 )
 
         return 200, await self.handler.federation_space_summary(
-            room_id, suggested_only, max_rooms_per_space, exclude_rooms
+            origin, room_id, suggested_only, max_rooms_per_space, exclude_rooms
         )
 
     # TODO When switching to the stable endpoint, remove the POST handler.