kernel-rt is vulnerable to arbitrary code execution attacks. The vulnerability exists as arch/x86/kvm/mmu.c in the Linux kernel through 4.13.5, when nested virtualisation is used, does not properly traverse guest pagetable entries to resolve a guest virtual address, which allows L1 guest OS users to execute arbitrary code on the host OS or cause a denial of service (incorrect index during page walking, and host OS crash).
www.securityfocus.com/bid/101267
access.redhat.com/errata/RHSA-2018:0395
access.redhat.com/errata/RHSA-2018:0412
access.redhat.com/security/cve/CVE-2017-12188
access.redhat.com/security/cve/CVE-2017-18270
access.redhat.com/security/updates/classification/#important
bugzilla.redhat.com/show_bug.cgi?id=1500380
bugzilla.redhat.com/show_bug.cgi?id=1537671
patchwork.kernel.org/patch/9996579/
patchwork.kernel.org/patch/9996587/