profile.php in PunBB 1.2.1 allows remote attackers to cause a denial of service (account lockout) by setting the user's password to NULL.
https://exchange.xforce.ibmcloud.com/vulnerabilities/19483
https://euvd.enisa.europa.eu/vulnerability/EUVD-2005-0571
http://www.securityfocus.com/bid/12652