diff --git a/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php b/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php
index e3d7a82466992b9e49e32cefdc69cb5c223bad3b..6147b4ec8f6b94895e02d515fae4235bdc5ac6ac 100644
--- a/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php
+++ b/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php
@@ -687,6 +687,9 @@ class ContentObjectRenderer implements LoggerAwareInterface
      */
     public function cObjGet($setup, $addKey = '')
     {
+        if (!is_array($setup)) {
+            return '';
+        }
         return implode('', $this->cObjGetSeparated($setup, $addKey));
     }
 
@@ -698,7 +701,7 @@ class ContentObjectRenderer implements LoggerAwareInterface
      */
     public function cObjGetSeparated(?array $setup, string $addKey = ''): array
     {
-        if (!is_array($setup) || $setup === []) {
+        if ($setup === null || $setup === []) {
             return [];
         }
         $sKeyArray = ArrayUtility::filterAndSortByNumericKeys($setup);