Multiple integer overflows in the (1) pppol2tp_sendmsg function in net/l2tp/l2tp_ppp.c, and the (2) l2tp_ip_sendmsg function in net/l2tp/l2tp_ip.c, in the PPPoL2TP and IPoL2TP implementations in the Linux kernel before 2.6.36.2 allow local users to cause a denial of service (heap memory corruption and panic) or possibly gain privileges via a crafted sendto call.