diff --git a/core/modules/file/file.js b/core/modules/file/file.js
index ad147d17ffdff9ef651549a92ea19d898b6e4b2a..b7289784fa49231f41710cf8aa9ea01f7d970b46 100644
--- a/core/modules/file/file.js
+++ b/core/modules/file/file.js
@@ -99,7 +99,7 @@ Drupal.file = Drupal.file || {
           '%filename': this.value.replace('C:\\fakepath\\', ''),
           '%extensions': extensionPattern.replace(/\|/g, ', ')
         });
-        $(this).closest('div.form-managed-file').prepend('<div class="messages error file-upload-js-error">' + error + '</div>');
+        $(this).closest('div.form-managed-file').prepend('<div class="messages error file-upload-js-error" aria-live="polite">' + error + '</div>');
         this.value = '';
       }
     }