--- drupal-6.6-orig/includes/theme.inc	2008-10-16 15:50:59.000000000 +0200
+++ drupal-6.6/includes/theme.inc	2008-11-28 23:05:31.000000000 +0100
@@ -1754,15 +1754,15 @@
   // Construct page title
   if (drupal_get_title()) {
     $head_title = array(strip_tags(drupal_get_title()), variable_get('site_name', 'Drupal'));
   }
   else {
     $head_title = array(variable_get('site_name', 'Drupal'));
     if (variable_get('site_slogan', '')) {
-      $head_title[] = variable_get('site_slogan', '');
+      $head_title[] = strip_tags(variable_get('site_slogan', ''));
     }
   }
   $variables['head_title']        = implode(' | ', $head_title);
   $variables['base_path']         = base_path();
   $variables['front_page']        = url();
   $variables['breadcrumb']        = theme('breadcrumb', drupal_get_breadcrumb());
   $variables['feed_icons']        = drupal_get_feeds();