* Fix can bypass permissions.

module/misc/control.php

@@ -230,6 +230,7 @@ class misc extends control
      */
     public function captcha($sessionVar = 'captcha', $uuid = '')
     {
+        if($sessionVar == 'user') die('The string user is not allowed to be defined as a session field.');
         $obLevel = ob_get_level();
         for($i = 0; $i < $obLevel; $i++) ob_end_clean();
 

module/user/model.php

@@ -1199,7 +1199,8 @@ class userModel extends model
      */
     public function isLogon()
     {
-        return ($this->session->user and $this->session->user->account != 'guest');
+        $user = $this->session->user;
+        return ($user and !empty($user->account) and $user->account != 'guest');
     }
 
     /**