libuser 0.56 and 0.57 has a TOCTOU (time-of-check time-of-use) race condition when copying and removing directory trees.
https://www.securityfocus.com/bid/59285
https://security-tracker.debian.org/tracker/CVE-2012-5630
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2012-5630
https://access.redhat.com/security/cve/cve-2012-5630
http://lists.fedoraproject.org/pipermail/package-announce/2013-April/102068.html