The sctp_sf_do_5_1D_ce function in net/sctp/sm_statefuns.c in the Linux kernel through 3.13.6 does not validate certain auth_enable and auth_capable fields before making an sctp_sf_authenticate call, which allows remote attackers to cause a denial of service (NULL pointer dereference and system crash) via an SCTP handshake with a modified INIT chunk and a crafted AUTH chunk before a COOKIE_ECHO chunk.