The Password policy module 6.x-1.x before 6.x-1.5 and 7.x-1.x before 7.x-1.3 for Drupal allows remote attackers to obtain password hashes by sniffing the network, related to "client-side password history checks."
http://www.securityfocus.com/bid/56350
http://www.openwall.com/lists/oss-security/2012/11/20/4
http://drupal.org/node/1828340