The msr_mtrr_valid function in arch/x86/kvm/mtrr.c in the Linux kernel before 4.6.1 supports MSR 0x2f8, which allows guest OS users to read or write to the kvm_arch_vcpu data structure, and consequently obtain sensitive information or cause a denial of service (system crash), via a crafted ioctl call.
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.6.1
http://www.openwall.com/lists/oss-security/2016/05/16/2
https://bugzilla.redhat.com/show_bug.cgi?id=1332139
https://github.com/torvalds/linux/commit/9842df62004f366b9fed2423e24df10542ee0dc5
Source: MITRE
Published: 2016-06-27
Updated: 2016-06-27
Type: CWE-284
Base Score: 5.6
Vector: AV:L/AC:L/Au:N/C:P/I:N/A:C
Impact Score: 7.8
Exploitability Score: 3.9
Severity: MEDIUM
Base Score: 7.1
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Impact Score: 5.2
Exploitability Score: 1.8
Severity: HIGH