CVE-2016-4440

Publication date 27 June 2016

Last updated 25 August 2025

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

7.8 · High

Score breakdown

Description

arch/x86/kvm/vmx.c in the Linux kernel through 4.6.3 mishandles the APICv on/off state, which allows guest OS users to obtain direct APIC MSR access on the host OS, and consequently cause a denial of service (host OS crash) or possibly execute arbitrary code on the host OS, via x2APIC mode.

From the Ubuntu Security Team

XXX-no-USN-needed-see-NOTE-XXX It was discovered that the Linux kernel mishandles the APICv on/off state, allowing guest OS users direct APIC MSR access on the host OS. A local attacker could use this to cause a denial of service (host OS crash), or possibly execute arbitrary code with administrative privileges in the host OS.

Read the notes from the security team

Status

Package Ubuntu Release Status
linux-aws 16.10 yakkety Not in release
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
12.04 LTS precise Not in release
linux-flo 16.10 yakkety
Not affected
16.04 LTS xenial Not in release
15.10 wily
Not affected
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-gke 16.10 yakkety Not in release
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-hwe 16.10 yakkety Not in release
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-hwe-edge 16.10 yakkety Not in release
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-lts-quantal 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Ignored end of life
linux-lts-raring 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Ignored end of life
linux-lts-saucy 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Ignored end of life
linux-lts-trusty 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise
Not affected
linux-lts-utopic 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-lts-vivid 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-lts-wily 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-lts-xenial 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty
Not affected
12.04 LTS precise Not in release
linux-qcm-msm 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Ignored end of life
linux-raspi2 16.10 yakkety
Not affected
16.04 LTS xenial
Not affected
15.10 wily
Not affected
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-snapdragon 16.10 yakkety
Not affected
16.04 LTS xenial
Not affected
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-ti-omap4 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise
Not affected
linux 16.10 yakkety
Not affected
16.04 LTS xenial
Not affected
15.10 wily
Not affected
14.04 LTS trusty
Not affected
12.04 LTS precise
Not affected
linux-armadaxp 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise
Not affected
linux-goldfish 16.10 yakkety
Not affected
16.04 LTS xenial Not in release
15.10 wily
Not affected
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-grouper 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-linaro-omap 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Ignored end of life
linux-linaro-shared 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Ignored end of life
linux-linaro-vexpress 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Ignored end of life
linux-maguro 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-mako 16.10 yakkety
Not affected
16.04 LTS xenial Not in release
15.10 wily
Not affected
14.04 LTS trusty Not in release
12.04 LTS precise Not in release
linux-manta 16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily
Not affected
14.04 LTS trusty Not in release
12.04 LTS precise Not in release

Notes

jdstrand

android kernels (flo, goldfish, grouper, maguro, mako and manta) are not supported on the Ubuntu Touch 14.10 and earlier preview kernels linux-lts-saucy no longer receives official support linux-lts-quantal no longer receives official support

sbeattie

according to kvm-devel thread, introduced in 5c919412fe61c35947816fdbd5f7bd09fe0dd073 note for xenial kernels, both the commit that introduced the issue and the fix were pulled in to the 4.4.0-32.51 kernel, so at no time were users exposed to this vulnerability.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
linux

Severity score breakdown

Parameter Value
Base score 7.8 · High
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Other references