diff --git a/wp-admin/includes/update.php b/wp-admin/includes/update.php
index 679b5ffa10..8b7d712d66 100644
--- a/wp-admin/includes/update.php
+++ b/wp-admin/includes/update.php
@@ -388,6 +388,7 @@ function wp_update_core($feedback = '') {
 		$wp_filesystem->delete($working_dir, true);
 		return new WP_Error('copy_failed', __('Could not copy files'));
 	}
+	$wp_filesystem->chmod($wp_dir . 'wp-admin/includes/update-core.php', 0644);
 
 	require(ABSPATH . 'wp-admin/includes/update-core.php');