diff --git a/core/modules/config/lib/Drupal/config/Controller/ConfigController.php b/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
index ff91637..eeec671 100644
--- a/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
+++ b/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
@@ -85,9 +85,11 @@ public function downloadExport() {
     file_unmanaged_delete(file_directory_temp() . '/config.tar.gz');
 
     $archiver = new ArchiveTar(file_directory_temp() . '/config.tar.gz', 'gz');
-    foreach ($this->targetStorage->listAll() as $name) {
-      $archiver->addString("$name.yml", Yaml::encode(\Drupal::config($name)->get()));
+    // Get raw configuration data without overrides.
+    foreach ($this->configManager->getConfigFactory()->listAll() as $name) {
+      $archiver->addString("$name.yml", Yaml::encode($this->configManager->getConfigFactory()->get($name)->getRawData()));
     }
+    // Get all override data from the remaining collections.
     foreach ($this->targetStorage->getAllCollectionNames() as $collection) {
       $collection_storage = $this->targetStorage->createCollection($collection);
       foreach ($collection_storage->listAll() as $name) {
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigExportUITest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigExportUITest.php
index cd486fe..c8987d1 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigExportUITest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigExportUITest.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\config\Tests;
 
+use Drupal\Component\Serialization\Yaml;
 use Drupal\Core\Archiver\Tar;
 use Drupal\simpletest\WebTestBase;
 
@@ -73,6 +74,12 @@ function testExport() {
     // Assert that the downloaded archive file contents are the same as the test
     // site active store.
     $this->assertIdentical($archive_contents, $config_files);
+
+    // Ensure the test configuration override did not end up exported.
+    $archiver->extract(file_directory_temp(), array('system.maintenance.yml'));
+    $file_contents = file_get_contents(file_directory_temp() . '/' . 'system.maintenance.yml');
+    $exported = Yaml::decode($file_contents);
+    $this->assertNotIdentical($exported['message'], 'Foo');
   }
 
 }
diff --git a/core/modules/config/tests/config_test/config_test.module b/core/modules/config/tests/config_test/config_test.module
index 77826e0..527fcc6 100644
--- a/core/modules/config/tests/config_test/config_test.module
+++ b/core/modules/config/tests/config_test/config_test.module
@@ -10,6 +10,9 @@
 
 require_once dirname(__FILE__) . '/config_test.hooks.inc';
 
+// Override the system maintenance message for testing.
+$GLOBALS['config']['system.maintenance']['message'] = 'Foo';
+
 /**
  * Loads a ConfigTest object.
  *