diff --git a/Classes/Domain/Validator/AbstractValidator.php b/Classes/Domain/Validator/AbstractValidator.php
index e7414ae80..b80134f1f 100644
--- a/Classes/Domain/Validator/AbstractValidator.php
+++ b/Classes/Domain/Validator/AbstractValidator.php
@@ -100,6 +100,6 @@ public function initFlexform(): void
 
     public function isConfirmationActivated(): bool
     {
-        return $this->flexForm['settings']['flexform']['main']['confirmation'] === '1';
+        return ($this->flexForm['settings']['flexform']['main']['confirmation'] ?? '') === '1';
     }
 }