Ticket #20846: 20846.patch

wp-comments-post.php

@@ -55 +55 @@
 // If the user is logged in
 $user = wp_get_current_user();
 if ( $user->exists() ) {
+        if ( is_multisite() && ! is_user_member_of_blog() )
+                wp_die( __('Sorry, you are not allowed to post comments on this site.') );
         if ( empty( $user->display_name ) )
                 $user->display_name=$user->user_login;
         $comment_author       = $wpdb->escape($user->display_name);