--- a/typo3/sysext/core/Classes/Domain/Repository/PageRepository.php
+++ b/typo3/sysext/core/Classes/Domain/Repository/PageRepository.php
@@ -1149,7 +1149,7 @@
     public function getExtURL($pagerow)
     {
         if ((int)$pagerow['doktype'] === self::DOKTYPE_LINK) {
-            $redirectTo = $pagerow['url'];
+            if (isset($pagerow['url']) && $pagerow['url']!='') { $redirectTo = $pagerow['url']; } else { return false; }
             $uI = parse_url($redirectTo);
             // If relative path, prefix Site URL
             // If it's a valid email without protocol, add "mailto:"