1 files changed, 7 insertions, 0 deletions
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 4a13f7e2e1..4fdc779b4b 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -207,6 +207,13 @@ class Auth(object):
                 user_id, room_id
             ))
 
+        if membership == Membership.LEAVE:
+            forgot = yield self.store.did_forget(user_id, room_id)
+            if forgot:
+                raise AuthError(403, "User %s not in room %s" % (
+                    user_id, room_id
+                ))
+
         defer.returnValue(member)
 
     @defer.inlineCallbacks