The mm subsystem in the Linux kernel through 3.2 does not properly enforce the CONFIG_STRICT_DEVMEM protection mechanism, which allows local users to read or write to kernel memory locations in the first megabyte (and bypass slab-allocation access restrictions) via an application that opens the /dev/mem file, related to arch/x86/mm/init.c and drivers/char/mem.c.
git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=a4866aa812518ed1a37d8ea0c881dc946409de94
www.debian.org/security/2017/dsa-3945
www.openwall.com/lists/oss-security/2017/04/16/4
www.securityfocus.com/bid/97690
access.redhat.com/errata/RHSA-2017:1842
access.redhat.com/errata/RHSA-2017:2077
access.redhat.com/errata/RHSA-2017:2669
access.redhat.com/errata/RHSA-2018:1854
git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=b8f254aa17f720053054c4ecff3920973a83b9d6
github.com/torvalds/linux/commit/a4866aa812518ed1a37d8ea0c881dc946409de94
usn.ubuntu.com/3583-1/
usn.ubuntu.com/3583-2/