2 files changed, 2 insertions, 2 deletions
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 49f8aa25ea..a9364670a1 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -1401,7 +1401,7 @@ class EventCreationHandler:
         ]
 
         for k in immutable_fields:
-            if getattr(builder, k, None) != original_event.get(k):
+            if getattr(builder, k, None) != getattr(original_event, k, None):
                 raise Exception(
                     "Third party rules module created an invalid event: "
                     "cannot change field " + k
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 5a888b7941..88e9d0e2fe 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -475,7 +475,7 @@ class RoomCreationHandler(BaseHandler):
             ):
                 await self.room_member_handler.update_membership(
                     requester,
-                    UserID.from_string(old_event["state_key"]),
+                    UserID.from_string(old_event.state_key),
                     new_room_id,
                     "ban",
                     ratelimit=False,