diff --git a/src/Symfony/Component/HttpKernel/Bundle/Bundle.php b/src/Symfony/Component/HttpKernel/Bundle/Bundle.php
index 0f8f84508266c..b1f7c7c60a12e 100644
--- a/src/Symfony/Component/HttpKernel/Bundle/Bundle.php
+++ b/src/Symfony/Component/HttpKernel/Bundle/Bundle.php
@@ -25,7 +25,7 @@
 abstract class Bundle implements BundleInterface
 {
     protected string $name;
-    protected ExtensionInterface|false $extension;
+    protected ExtensionInterface|false|null $extension = null;
     protected string $path;
     protected ?ContainerInterface $container;