diff -u b/core/lib/Drupal/Component/Utility/UrlHelper.php b/core/lib/Drupal/Component/Utility/UrlHelper.php
--- b/core/lib/Drupal/Component/Utility/UrlHelper.php
+++ b/core/lib/Drupal/Component/Utility/UrlHelper.php
@@ -3,6 +3,8 @@
 namespace Drupal\Component\Utility;
 
 use Symfony\Component\Validator\Constraints\Url;
+use Symfony\Component\Validator\Constraints\NotBlank;
+use Symfony\Component\Validator\Constraints\NotBlankValidator;
 use Symfony\Component\Validator\Validation;
 
 /**
@@ -398,6 +400,7 @@
     if ($absolute) {
       $violations = Validation::createValidator()->validate($url, [
         new Url(['protocols' => ['http', 'https', 'ftp', 'feed']]),
+        new NotBlank(),
       ]);
       return !(bool) count($violations);
     }
diff -u b/core/tests/Drupal/Tests/Component/Utility/UrlHelperTest.php b/core/tests/Drupal/Tests/Component/Utility/UrlHelperTest.php
--- b/core/tests/Drupal/Tests/Component/Utility/UrlHelperTest.php
+++ b/core/tests/Drupal/Tests/Component/Utility/UrlHelperTest.php
@@ -223,6 +223,7 @@
       ['foo.bar/', 'ftps'],
       ['foo.com', ''],
       ['test', ''],
+      ['', ''],
     ];
     return array_merge($schemes, $this->dataEnhanceWithScheme($data));
   }