diff --git a/src/Symfony/Component/HttpKernel/Debug/FileLinkFormatter.php b/src/Symfony/Component/HttpKernel/Debug/FileLinkFormatter.php
index 2879273005428..fc85efce4ae00 100644
--- a/src/Symfony/Component/HttpKernel/Debug/FileLinkFormatter.php
+++ b/src/Symfony/Component/HttpKernel/Debug/FileLinkFormatter.php
@@ -35,8 +35,8 @@ class FileLinkFormatter
     ];
 
     private array|false $fileLinkFormat;
-    private ?RequestStack $requestStack;
-    private ?string $baseDir;
+    private ?RequestStack $requestStack = null;
+    private ?string $baseDir = null;
     private \Closure|string|null $urlFormat;
 
     /**
diff --git a/src/Symfony/Component/HttpKernel/Tests/Debug/FileLinkFormatterTest.php b/src/Symfony/Component/HttpKernel/Tests/Debug/FileLinkFormatterTest.php
index 548112ad52fef..35a4e1658eb48 100644
--- a/src/Symfony/Component/HttpKernel/Tests/Debug/FileLinkFormatterTest.php
+++ b/src/Symfony/Component/HttpKernel/Tests/Debug/FileLinkFormatterTest.php
@@ -25,6 +25,13 @@ public function testWhenNoFileLinkFormatAndNoRequest()
         $this->assertFalse($sut->format('/kernel/root/src/my/very/best/file.php', 3));
     }
 
+    public function testAfterUnserialize()
+    {
+        $sut = unserialize(serialize(new FileLinkFormatter()));
+
+        $this->assertFalse($sut->format('/kernel/root/src/my/very/best/file.php', 3));
+    }
+
     public function testWhenFileLinkFormatAndNoRequest()
     {
         $file = __DIR__.\DIRECTORY_SEPARATOR.'file.php';