diff --git a/lib/Models/Subscriber.php b/lib/Models/Subscriber.php
index aa8e420fd9..14dddeb2a5 100644
--- a/lib/Models/Subscriber.php
+++ b/lib/Models/Subscriber.php
@@ -150,7 +150,7 @@ class Subscriber extends Model {
   }
 
   static function verifyToken($email, $token) {
-    return hash_equals(self::generateToken($email), $token);
+    return call_user_func('hash_equals', self::generateToken($email), $token);
   }
 
   static function subscribe($subscriber_data = array(), $segment_ids = array()) {