The DNS resolution functionality in the CIFS implementation in the Linux kernel before 2.6.35, when CONFIG_CIFS_DFS_UPCALL is enabled, relies on a user's keyring for the dns_resolver upcall in the cifs.upcall userspace helper, which allows local users to spoof the results of DNS queries and perform arbitrary CIFS mounts via vectors involving an add_key call, related to a "cache stuffing" issue and MS-DFS referrals.
https://bugzilla.redhat.com/show_bug.cgi?id=612166
http://www.vmware.com/security/advisories/VMSA-2011-0003.html
http://www.ubuntu.com/usn/USN-1000-1
http://www.securityfocus.com/archive/1/516397/100/0/threaded
http://marc.info/?l=oss-security&m=128080755321157&w=2
http://marc.info/?l=oss-security&m=128078387328921&w=2
http://marc.info/?l=oss-security&m=128072090331700&w=2
http://lists.opensuse.org/opensuse-security-announce/2010-09/msg00004.html