libuser 0.51.7 allows attackers to cause a denial of service (crash or disk consumption) via unknown attack vectors, related to read failures and other bugs.
https://exchange.xforce.ibmcloud.com/vulnerabilities/16188
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=120168
http://www.securityfocus.com/bid/10368
http://www.redhat.com/support/errata/RHSA-2005-770.html
http://www.mandriva.com/security/advisories?name=MDKSA-2004:044