The xfrm_migrate() function in the net/xfrm/xfrm_policy.c file in the Linux kernel built with CONFIG_XFRM_MIGRATE does not verify if the dir parameter is less than XFRM_POLICY_MAX. This allows a local attacker to cause a denial of service (out-of-bounds access) or possibly have unspecified other impact by sending a XFRM_MSG_MIGRATE netlink message. This flaw is present in the Linux kernel since an introduction of XFRM_MSG_MIGRATE in 2.6.21-rc1, up to 4.13-rc3.