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.
Exploitability
AV:NAC:MAu:NImpact
C:PI:PA:P6.8/AV:N/AC:M/Au:N/C:P/I:P/A:P