The NFSv4 server in the Linux kernel before 4.11.3 does not properly validate the layout type when processing the NFSv4 pNFS GETDEVICEINFO or LAYOUTGET operand in a UDP packet from a remote attacker. This type value is uninitialized upon encountering certain error conditions. This value is used as an array index for dereferencing, which leads to an OOPS and eventually a DoS of knfsd and a soft-lockup of the whole system.
https://github.com/torvalds/linux/commit/f961e3f2acae94b727380c0b74e2d3954d0edf79
https://github.com/torvalds/linux/commit/b550a32e60a4941994b437a8d662432a486235a5
https://bugzilla.redhat.com/show_bug.cgi?id=1466329
https://access.redhat.com/errata/RHSA-2017:2669
https://access.redhat.com/errata/RHSA-2017:2437
https://access.redhat.com/errata/RHSA-2017:2077
https://access.redhat.com/errata/RHSA-2017:1842
http://www.securitytracker.com/id/1038790
http://www.securityfocus.com/bid/99298
http://www.openwall.com/lists/oss-security/2017/06/27/5
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.11.3