Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.953
diff -u -p -r1.953 common.inc
--- includes/common.inc	4 Aug 2009 06:38:56 -0000	1.953
+++ includes/common.inc	5 Aug 2009 16:56:40 -0000
@@ -3555,6 +3555,13 @@ function drupal_cron_run() {
   // Allow execution to continue even if the request gets canceled.
   @ignore_user_abort(TRUE);
 
+  // Force the current user to anonymous to ensure consistent permissions on
+  // cron runs.
+  $GLOBALS['user'] = drupal_anonymous_user();
+
+  // Prevent session information from being saved.
+  drupal_save_session(FALSE);
+
   // Try to increase the maximum execution time if it is too low.
   if (ini_get('max_execution_time') < 240) {
     @set_time_limit(240);