diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py
index 92fcae674a..d8c76a3465 100644
--- a/synapse/rest/client/v1/login.py
+++ b/synapse/rest/client/v1/login.py
@@ -427,6 +427,7 @@ class CasTicketServlet(ClientV1RestServlet):
         self.cas_server_url = hs.config.cas_server_url
         self.cas_service_url = hs.config.cas_service_url
         self.cas_required_attributes = hs.config.cas_required_attributes
+        self.auth_handler = hs.get_auth_handler()
 
     @defer.inlineCallbacks
     def on_GET(self, request):