Ticket #27869: 27869.diff

src/wp-admin/includes/ajax-actions.php

@@ -2233 +2233 @@
                 wp_send_json_error();
         }
 
-        $update_php = self_admin_url( 'update.php?action=install-theme' );
+        $update_php = network_admin_url( 'update.php?action=install-theme' );
         foreach ( $api->themes as &$theme ) {
                 $theme->install_url = add_query_arg( array(
                         'theme'    => $theme->slug,