The replace_map_fd_with_map_ptr function in kernel/bpf/verifier.c in the Linux kernel before 4.5.5 does not properly maintain an fd data structure, which allows local users to gain privileges or cause a denial of service (use-after-free) via crafted BPF instructions that reference an incorrect file descriptor.
https://www.exploit-db.com/exploits/40759/
https://github.com/torvalds/linux/commit/8358b02bf67d3a5d8a825070e1aa73f25fb2e4c7
https://bugzilla.redhat.com/show_bug.cgi?id=1334307
https://bugs.debian.org/823603
https://bugs.chromium.org/p/project-zero/issues/detail?id=808
http://www.openwall.com/lists/oss-security/2016/05/06/4
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.5.5
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00044.html