diff --git a/lib/navigation.php b/lib/navigation.php
index 6d63267..1ab0549 100644
--- a/lib/navigation.php
+++ b/lib/navigation.php
@@ -1,8 +1,14 @@
 <?php
 
 function getDynamicPermission($file): int {
+    global $routerConfig;
     $page_tmp = include_once($file);
-    return $page_tmp["parameters"]["minimal_permission_level"];
+    $permission_level = $page_tmp["parameters"]["minimal_permission_level"];
+
+    if(!is_numeric($permission_level) || $permission_level <= 0){
+        $permission_level = $routerConfig["default_page_permission_level"];
+    }
+    return $permission_level;
 }
 
 function generateNavigation(): string