The crack gem 0.3.1 and earlier for Ruby does not properly restrict casts of string values, which might allow remote attackers to conduct object-injection attacks and execute arbitrary code, or cause a denial of service (memory and CPU consumption) by leveraging Action Pack support for (1) YAML type conversion or (2) Symbol type conversion, a similar vulnerability to CVE-2013-0156.
https://bugzilla.redhat.com/show_bug.cgi?id=917236
https://bugzilla.novell.com/show_bug.cgi?id=804721
http://secunia.com/advisories/52897
http://lists.opensuse.org/opensuse-security-announce/2013-04/msg00003.html