diff --git a/Classes/ViewHelpers/Be/ExtensionActiveViewHelper.php b/Classes/ViewHelpers/Be/ExtensionActiveViewHelper.php
index 0aff540e..8434aeb1 100644
--- a/Classes/ViewHelpers/Be/ExtensionActiveViewHelper.php
+++ b/Classes/ViewHelpers/Be/ExtensionActiveViewHelper.php
@@ -33,7 +33,7 @@ public function initializeArguments(): void
 
     public static function verdict(array $arguments, RenderingContextInterface $renderingContext): bool
     {
-        if (ExtensionManagementUtility::isLoaded($arguments['extension'])) {
+        if (ExtensionManagementUtility::isLoaded((string)($arguments['extension'] ?? ''))) {
             return true;
         }
         return false;
diff --git a/Tests/Functional/ViewHelpers/ExtensionActiveViewHelperTest.php b/Tests/Functional/ViewHelpers/ExtensionActiveViewHelperTest.php
index 9648268f..dd4a215d 100644
--- a/Tests/Functional/ViewHelpers/ExtensionActiveViewHelperTest.php
+++ b/Tests/Functional/ViewHelpers/ExtensionActiveViewHelperTest.php
@@ -53,7 +53,7 @@ public static function renderDataProvider(): \Generator
             [],
             'elseArgument',
         ];
-        
+
         yield 'extension provided as undefined fluid variable placeholder, await else' => [
             '<deepl:be.extensionActive extension="{someUndefinedVariable}" then="thenArgument" else="elseArgument" />',
             [],