diff --git a/synapse/handlers/room_summary.py b/synapse/handlers/room_summary.py
index 64f5bea014f..045a35c6ae1 100644
--- a/synapse/handlers/room_summary.py
+++ b/synapse/handlers/room_summary.py
@@ -955,7 +955,7 @@ def as_json(self, for_client: bool = False) -> JsonDict:
 
 def _has_valid_via(e: EventBase) -> bool:
     via = e.content.get("via")
-    if not via or not isinstance(via, list):
+    if not via or not isinstance(via, (tuple, list)):
         return False
     for v in via:
         if not isinstance(v, str):