wp-includes/pluggable.php in WordPress before 3.9.2 does not use delimiters during concatenation of action values and uid values in CSRF tokens, which makes it easier for remote attackers to bypass a CSRF protection mechanism via a brute-force attack.
http://openwall.com/lists/oss-security/2014/08/13/3
http://www.debian.org/security/2014/dsa-3001