diff --git a/polynum/base/backends.py b/polynum/base/backends.py
index 8d3f408..561c0b5 100644
--- a/polynum/base/backends.py
+++ b/polynum/base/backends.py
@@ -57,7 +57,7 @@ class CASBackend(PolynumBackendMixin, CASBackend):
         return r
 
     def authenticate(self, ticket, service):
-        username = _verify(ticket, service)
+        username, attributes = _verify(ticket, service)
         if not username:
             return None
         try: