diff --git modules/filter/filter.module modules/filter/filter.module
index 7d49422..9487491 100644
--- modules/filter/filter.module
+++ modules/filter/filter.module
@@ -1219,7 +1219,7 @@ function _filter_xss_attributes($attr) {
 function filter_xss_bad_protocol($string, $decode = TRUE) {
   static $allowed_protocols;
   if (!isset($allowed_protocols)) {
-    $allowed_protocols = array_flip(variable_get('filter_allowed_protocols', array('http', 'https', 'ftp', 'news', 'nntp', 'telnet', 'mailto', 'irc', 'ssh', 'sftp', 'webcal', 'rtsp')));
+    $allowed_protocols = array_flip(variable_get('filter_allowed_protocols', array('http', 'https', 'ftp', 'news', 'nntp', 'telnet', 'mailto', 'irc', 'ssh', 'sftp', 'webcal', 'rtsp', 'internal')));
   }
 
   // Get the plain text representation of the attribute value (i.e. its meaning).