diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 7f8ddc99c..a0cf37a9f 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -479,6 +479,7 @@ class AuthHandler(BaseHandler):
                 medium,
                 threepid_creds["client_secret"],
                 sid=threepid_creds["sid"],
+                validated=True,
             )
 
             threepid = {
diff --git a/synapse/storage/registration.py b/synapse/storage/registration.py
index 9b41cbd75..1dd1182e8 100644
--- a/synapse/storage/registration.py
+++ b/synapse/storage/registration.py
@@ -998,7 +998,7 @@ class RegistrationStore(
         client_secret,
         address=None,
         sid=None,
-        validated=None,
+        validated=True,
     ):
         """Gets a session_id and last_send_attempt (if available) for a
         client_secret/medium/(address|session_id) combo