The Linux kernel before 2.6.12.5 does not properly destroy a keyring that is not instantiated properly, which allows local users or remote attackers to cause a denial of service (kernel oops) via a keyring with a payload that is not empty, which causes the creation to fail, leading to a null dereference in the keyring destructor.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A9079
http://www.securityfocus.com/bid/14517
http://www.securityfocus.com/archive/1/427980/100/0/threaded
http://www.redhat.com/support/errata/RHSA-2005-514.html
http://www.mandriva.com/security/advisories?name=MDKSA-2005:220
http://securitytracker.com/id?1014644
http://secunia.com/advisories/17073