The ip6_dst_lookup_tail function in net/ipv6/ip6_output.c in the Linux kernel before 2.6.27 does not properly handle certain circumstances involving an IPv6 TUN network interface and a large number of neighbors, which allows attackers to cause a denial of service (NULL pointer dereference and OOPS) or possibly have unspecified other impact via unknown vectors.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10061
https://bugzilla.redhat.com/show_bug.cgi?id=563781
http://www.vmware.com/security/advisories/VMSA-2011-0003.html
http://www.securityfocus.com/archive/1/516397/100/0/threaded
http://www.redhat.com/support/errata/RHSA-2010-0161.html
http://www.redhat.com/support/errata/RHSA-2010-0147.html
http://www.openwall.com/lists/oss-security/2010/03/04/4
http://www.openwall.com/lists/oss-security/2010/02/11/1
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.27
http://secunia.com/advisories/43315