diff --git a/filter/algebra/algebradebug.php b/filter/algebra/algebradebug.php
index ff7f1ade203..05f82eed83e 100644
--- a/filter/algebra/algebradebug.php
+++ b/filter/algebra/algebradebug.php
@@ -25,6 +25,8 @@
       $CFG->algebrafilterdirwin = "filter\\algebra";
     }
 
+    require_login();
+    require_capability('moodle/site:config', get_context_instance(CONTEXT_SYSTEM));
 
     $query = urldecode($_SERVER['QUERY_STRING']);
     error_reporting(E_ALL);