The SMB2_tcon function in fs/cifs/smb2pdu.c in the Linux kernel before 3.16.3 allows remote CIFS servers to cause a denial of service (NULL pointer dereference and client system crash) or possibly have unspecified other impact by deleting the IPC$ share during resolution of DFS referrals.
http://rhn.redhat.com/errata/RHSA-2015-0102.html
https://github.com/torvalds/linux/commit/18f39e7be0121317550d03e267e3ebd4dbfbb3ce
http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.16.3