Ticket #17303: 17303.patch

wp-includes/ms-functions.php

@@ -687 +687 @@
                 $mydomain = "$domain";
                 $path = $base.$blogname.'/';
         }
-        if ( domain_exists($mydomain, $path) )
+        if ( domain_exists($mydomain, $path, $current_site->id) )
                 $errors->add('blogname', __('Sorry, that site already exists!'));
 
         if ( username_exists( $blogname ) ) {