diff --git a/wp-admin/setup-config.php b/wp-admin/setup-config.php
index f89968ca28..7e06726443 100644
--- a/wp-admin/setup-config.php
+++ b/wp-admin/setup-config.php
@@ -426,33 +426,63 @@ if ( ! /iPad|iPod|iPhone/.test( navigator.userAgent ) ) {
})();
+ $error_message = '';
+ $handle = fopen( $path_to_wp_config, 'w' );
+ /*
+ * Why check for the absence of false instead of checking for resource with is_resource()?
+ * To future-proof the check for when fopen returns object instead of resource, i.e. a known
+ * change coming in PHP.
+ */
+ if ( false !== $handle ) {
+ foreach ( $config_file as $line ) {
+ fwrite( $handle, $line );
+ }
+ fclose( $handle );
+ } else {
+ $wp_config_perms = fileperms( $path_to_wp_config );
+ if ( ! empty( $wp_config_perms ) && ! is_writable( $path_to_wp_config ) ) {
+ $error_message = sprintf(
+ /* translators: 1 wp-config.php, 2: Documentation URL. */
+ __( 'You need to make the file %1$s writable before you can save your changes. See Changing File Permissions for more information.' ),
+ 'wp-config.php
',
+ __( 'https://wordpress.org/support/article/changing-file-permissions/' )
+ );
+ } else {
+ $error_message = sprintf(
+ /* translators: %s: wp-config.php */
+ __( 'Unable to write to %s file.' ),
+ 'wp-config.php
'
+ );
+ }
+ }
+
+ chmod( $path_to_wp_config, 0666 );
+ setup_config_display_header();
+
+ if ( false !== $handle ) :
+ ?>