diff --git a/core/lib/Drupal/Core/Database/Database.php b/core/lib/Drupal/Core/Database/Database.php
index 354857616ad933cbcc681db519e068d10892ede2..4e87201fba8824d780c4eb1ad5f87c986cd04834 100644
--- a/core/lib/Drupal/Core/Database/Database.php
+++ b/core/lib/Drupal/Core/Database/Database.php
@@ -535,6 +535,7 @@ public static function convertDbUrlToConnectionInfo($url, $root, ?bool $include_
     // called during regular runtime.
     $additional_class_loader = new ClassLoader();
     $additional_class_loader->addPsr4($driverNamespace . '\\', $driver->getPath());
+    $additional_class_loader->register();
     $connection_class = $driverNamespace . '\\Connection';
     if (!class_exists($connection_class)) {
       throw new \InvalidArgumentException("Can not convert '$url' to a database connection, class '$connection_class' does not exist");