WordPress before 2.2.2 allows remote attackers to redirect visitors to other websites and potentially obtain sensitive information via (1) the _wp_http_referer parameter to wp-pass.php, related to the wp_get_referer function in wp-includes/functions.php; and possibly other vectors related to (2) wp-includes/pluggable.php and (3) the wp_nonce_ays function in wp-includes/functions.php.
