Ticket #61711: 61711-2.diff

src/wp-includes/class-wp.php

@@ -545 +545 @@
                         if ( $post && pings_open( $post ) ) {
                                 $headers['X-Pingback'] = get_bloginfo( 'pingback_url', 'display' );
                         }
+
+                        // Send nocache headers for password protected posts to avoid reverse-proxy or CDNs caching.
+                        if ( ! empty( $post->post_password ) ) {
+                                $headers = array_merge( $headers, wp_get_nocache_headers() );
+                        }
                 }
 
                 /**