The get_instantiation_keyring function in security/keys/keyctl.c in the KEYS subsystem in the Linux kernel before 2.6.32-rc5 does not properly maintain the reference count of a keyring, which allows local users to gain privileges or cause a denial of service (OOPS) via vectors involving calls to this function without specifying a keyring by ID, as demonstrated by a series of keyctl request2 and keyctl list commands.
http://www.ubuntu.com/usn/usn-864-1
http://www.kernel.org/pub/linux/kernel/v2.6/testing/ChangeLog-2.6.32-rc5
http://twitter.com/spendergrsec/statuses/4916661870
http://secunia.com/advisories/38017
http://secunia.com/advisories/37086
http://marc.info/?l=oss-security&m=125624091417161&w=2
http://marc.info/?l=oss-security&m=125619420905341&w=2
http://lists.opensuse.org/opensuse-security-announce/2010-01/msg00000.html