crypto/mcryptd.c in the Linux kernel before 4.8.15 allows local users to cause a denial of service (NULL pointer dereference and system crash) by using an AF_ALG socket with an incompatible algorithm, as demonstrated by mcryptd(md5).
https://github.com/torvalds/linux/commit/48a992727d82cb7db076fa15d372178743b1f4cd
https://bugzilla.redhat.com/show_bug.cgi?id=1404200
https://access.redhat.com/errata/RHSA-2017:2077
https://access.redhat.com/errata/RHSA-2017:1842
http://www.securityfocus.com/bid/95677
http://www.openwall.com/lists/oss-security/2017/01/17/13
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.8.15