CVE-2016-4440

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

Show unmaintained releases

Package	Ubuntu Release	Status
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-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 affected
	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-goldfish	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-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-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-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-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-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 affected
	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
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

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	Introduced by 5c91941, fixed by 3ce424e

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

Cvss 3 Severity Score