diff --git a/core/modules/system/src/FileDownloadController.php b/core/modules/system/src/FileDownloadController.php
index a65342d..3deb234 100644
--- a/core/modules/system/src/FileDownloadController.php
+++ b/core/modules/system/src/FileDownloadController.php
@@ -59,6 +59,9 @@ public function download(Request $request, $scheme = 'private') {
       }
 
       if (count($headers)) {
+        if ($scheme === 'private') {
+          $headers['cache-control'] = 'private';
+        }
         return new BinaryFileResponse($uri, 200, $headers);
       }