diff --git a/administrator/components/com_categories/src/Dispatcher/Dispatcher.php b/administrator/components/com_categories/src/Dispatcher/Dispatcher.php
index 595b5c4e01113..f3e95a9893510 100644
--- a/administrator/components/com_categories/src/Dispatcher/Dispatcher.php
+++ b/administrator/components/com_categories/src/Dispatcher/Dispatcher.php
@@ -31,7 +31,9 @@ class Dispatcher extends ComponentDispatcher
      */
     protected function checkAccess()
     {
-        $extension = $this->getApplication()->getInput()->getCmd('extension');
+        $extension = empty($this->getApplication()->getInput()->getCmd('extension'))
+                    ? ''
+                    : $this->getApplication()->getInput()->getCmd('extension');
 
         $parts = explode('.', $extension);