CVE-2019-3887

2019-04-0900:00:00

ubuntu.com

5.6 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H

4.7 Medium

CVSS2

Access Vector

LOCAL

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

COMPLETE

AV:L/AC:M/Au:N/C:N/I:N/A:C

0.001 Low

EPSS

Percentile

19.3%

JSON

A flaw was found in the way KVM hypervisor handled x2APIC Machine Specific
Rregister (MSR) access with nested(=1) virtualization enabled. In that, L1
guest could access L0’s APIC register values via L2 guest, when ‘virtualize
x2APIC mode’ is enabled. A guest could use this flaw to potentially crash
the host kernel resulting in DoS issue. Kernel versions from 4.16 and newer
are vulnerable to this issue.

Notes

Author	Note
tyhicks	Ubuntu kernels do not enable nested KVM virtualization by default and are unaffected by this flaw in the default configuration. However, installing QEMU results in nested KVM support to be enabled via the /etc/modprobe.d/qemu-system-x86.conf file. To ensure that nested virtualization is not enabled, verify that the /sys/module/kvm_intel/parameters/nested file contains “N”.

OSVersionArchitecturePackageVersionFilename
ubuntu18.10noarchlinux< 4.18.0-20.21UNKNOWN
ubuntu19.04noarchlinux< 5.0.0-15.16UNKNOWN
ubuntu18.10noarchlinux-aws< 4.18.0-1016.18UNKNOWN
ubuntu19.04noarchlinux-aws< 5.0.0-1006.6UNKNOWN
ubuntu18.04noarchlinux-azure< 4.18.0-1018.18~18.04.1UNKNOWN
ubuntu18.10noarchlinux-azure< 4.18.0-1018.18UNKNOWN
ubuntu19.04noarchlinux-azure< 5.0.0-1006.6UNKNOWN
ubuntu18.04noarchlinux-azure-edge< 4.18.0-1018.18~18.04.1UNKNOWN
ubuntu18.10noarchlinux-gcp< 4.18.0-1011.12UNKNOWN
ubuntu19.04noarchlinux-gcp< 5.0.0-1006.6UNKNOWN

OS	Version	Architecture	Package	Version	Filename
ubuntu	18.10	noarch	linux	< 4.18.0-20.21	UNKNOWN
ubuntu	19.04	noarch	linux	< 5.0.0-15.16	UNKNOWN
ubuntu	18.10	noarch	linux-aws	< 4.18.0-1016.18	UNKNOWN
ubuntu	19.04	noarch	linux-aws	< 5.0.0-1006.6	UNKNOWN
ubuntu	18.04	noarch	linux-azure	< 4.18.0-1018.18~18.04.1	UNKNOWN
ubuntu	18.10	noarch	linux-azure	< 4.18.0-1018.18	UNKNOWN
ubuntu	19.04	noarch	linux-azure	< 5.0.0-1006.6	UNKNOWN
ubuntu	18.04	noarch	linux-azure-edge	< 4.18.0-1018.18~18.04.1	UNKNOWN
ubuntu	18.10	noarch	linux-gcp	< 4.18.0-1011.12	UNKNOWN
ubuntu	19.04	noarch	linux-gcp	< 5.0.0-1006.6	UNKNOWN