wp-includes/pluggable.php in WordPress before 3.9.2 rejects invalid CSRF nonces with a different timing depending on which characters in the nonce are…

wp-includes/pluggable.php in WordPress before 3.9.2 rejects invalid CSRF nonces with a different timing depending on which characters in the nonce are incorrect, which makes it easier for remote attackers to bypass a CSRF protection mechanism via a brute-force attack.