net/xfrm/xfrm_policy.c in the Linux kernel through 4.12.3, when CONFIG_XFRM_MIGRATE is enabled, does not ensure that the dir value of xfrm_userpolicy_id is XFRM_POLICY_MAX or less, which allows local users to cause a denial of service (out-of-bounds access) or possibly have unspecified other impact via an XFRM_MSG_MIGRATE xfrm Netlink message.
Exploitability
AV:LAC:HPR:LUI:NScope
S:UImpact
C:HI:HA:H7/CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H