6.5
MEDIUM
CVE-2016-4020
QEMU KVMvapic Information Disclosure Vulnerability
Description

The patch_instruction function in hw/i386/kvmvapic.c in QEMU does not initialize the imm32 variable, which allows local guest OS administrators to obtain sensitive information from host stack memory by accessing the Task Priority Register (TPR).

INFO

Published Date :

May 25, 2016, 3:59 p.m.

Last Modified :

Feb. 13, 2023, 4:50 a.m.

Remotely Exploitable :

No

Impact Score :

4.0

Exploitability Score :

2.0
Affected Products

The following products are affected by CVE-2016-4020 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Redhat enterprise_linux_desktop
2 Redhat enterprise_linux_server
3 Redhat enterprise_linux_workstation
4 Redhat enterprise_linux_server_aus
5 Redhat enterprise_linux_server_tus
6 Redhat openstack
7 Redhat enterprise_linux_eus
8 Redhat virtualization
1 Canonical ubuntu_linux
1 Debian debian_linux
1 Qemu qemu
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2016-4020.

URL Resource
http://git.qemu.org/?p=qemu.git%3Ba=commit%3Bh=691a02e2ce0c413236a78dee6f2651c937b09fb0
http://www.securityfocus.com/bid/86067 Third Party Advisory VDB Entry
http://www.ubuntu.com/usn/USN-2974-1 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:1856 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:2392 Third Party Advisory
https://access.redhat.com/errata/RHSA-2017:2408 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1313686 Issue Tracking Third Party Advisory
https://lists.debian.org/debian-lts-announce/2018/11/msg00038.html Mailing List Third Party Advisory
https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg01106.html Patch Third Party Advisory
https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg01118.html Patch Third Party Advisory
https://security.gentoo.org/glsa/201609-01 Third Party Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2016-4020 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2016-4020 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Feb. 13, 2023

    Action Type Old Value New Value
    Changed Description An information-exposure flaw was found in Quick Emulator (QEMU) in Task Priority Register (TPR) optimizations for 32-bit Windows guests. The flaw could occur while accessing TPR. A privileged user inside a guest could use this issue to read portions of the host memory. The patch_instruction function in hw/i386/kvmvapic.c in QEMU does not initialize the imm32 variable, which allows local guest OS administrators to obtain sensitive information from host stack memory by accessing the Task Priority Register (TPR).
    Removed CVSS V2 Red Hat, Inc. (AV:A/AC:M/Au:N/C:P/I:N/A:N)
    Removed CVSS V3 Red Hat, Inc. AV:A/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N
    Removed Reference https://access.redhat.com/security/cve/CVE-2016-4020 [No Types Assigned]
  • CVE Modified by [email protected]

    Feb. 02, 2023

    Action Type Old Value New Value
    Changed Description The patch_instruction function in hw/i386/kvmvapic.c in QEMU does not initialize the imm32 variable, which allows local guest OS administrators to obtain sensitive information from host stack memory by accessing the Task Priority Register (TPR). An information-exposure flaw was found in Quick Emulator (QEMU) in Task Priority Register (TPR) optimizations for 32-bit Windows guests. The flaw could occur while accessing TPR. A privileged user inside a guest could use this issue to read portions of the host memory.
    Added CVSS V2 Red Hat, Inc. (AV:A/AC:M/Au:N/C:P/I:N/A:N)
    Added CVSS V3 Red Hat, Inc. AV:A/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N
    Removed Reference http://git.qemu.org/?p=qemu.git;a=commit;h=691a02e2ce0c413236a78dee6f2651c937b09fb0 [Patch, Vendor Advisory]
    Added Reference http://git.qemu.org/?p=qemu.git%3Ba=commit%3Bh=691a02e2ce0c413236a78dee6f2651c937b09fb0 [No Types Assigned]
    Added Reference https://access.redhat.com/security/cve/CVE-2016-4020 [No Types Assigned]
  • CPE Deprecation Remap by [email protected]

    Aug. 04, 2021

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:redhat:openstack:9.0:*:*:*:*:*:*:* OR *cpe:2.3:a:redhat:openstack:9:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    Aug. 04, 2021

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:redhat:openstack:11.0:*:*:*:*:*:*:* OR *cpe:2.3:a:redhat:openstack:11:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    Aug. 04, 2021

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:redhat:openstack:8.0:*:*:*:*:*:*:* OR *cpe:2.3:a:redhat:openstack:8:*:*:*:*:*:*:*
  • Modified Analysis by [email protected]

    Oct. 15, 2020

    Action Type Old Value New Value
    Removed CVSS V3 NIST AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
    Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
    Changed Reference Type http://git.qemu.org/?p=qemu.git;a=commit;h=691a02e2ce0c413236a78dee6f2651c937b09fb0 Vendor Advisory http://git.qemu.org/?p=qemu.git;a=commit;h=691a02e2ce0c413236a78dee6f2651c937b09fb0 Patch, Vendor Advisory
    Changed Reference Type http://www.securityfocus.com/bid/86067 No Types Assigned http://www.securityfocus.com/bid/86067 Third Party Advisory, VDB Entry
    Changed Reference Type http://www.ubuntu.com/usn/USN-2974-1 No Types Assigned http://www.ubuntu.com/usn/USN-2974-1 Third Party Advisory
    Changed Reference Type https://access.redhat.com/errata/RHSA-2017:1856 No Types Assigned https://access.redhat.com/errata/RHSA-2017:1856 Third Party Advisory
    Changed Reference Type https://access.redhat.com/errata/RHSA-2017:2392 No Types Assigned https://access.redhat.com/errata/RHSA-2017:2392 Third Party Advisory
    Changed Reference Type https://access.redhat.com/errata/RHSA-2017:2408 No Types Assigned https://access.redhat.com/errata/RHSA-2017:2408 Third Party Advisory
    Changed Reference Type https://bugzilla.redhat.com/show_bug.cgi?id=1313686 No Types Assigned https://bugzilla.redhat.com/show_bug.cgi?id=1313686 Issue Tracking, Third Party Advisory
    Changed Reference Type https://lists.debian.org/debian-lts-announce/2018/11/msg00038.html No Types Assigned https://lists.debian.org/debian-lts-announce/2018/11/msg00038.html Mailing List, Third Party Advisory
    Changed Reference Type https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg01106.html Vendor Advisory https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg01106.html Patch, Third Party Advisory
    Changed Reference Type https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg01118.html No Types Assigned https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg01118.html Patch, Third Party Advisory
    Changed Reference Type https://security.gentoo.org/glsa/201609-01 No Types Assigned https://security.gentoo.org/glsa/201609-01 Third Party Advisory
    Removed CWE NIST CWE-200
    Added CWE NIST NVD-CWE-noinfo
    Changed CPE Configuration OR *cpe:2.3:a:qemu:qemu:-:*:*:*:*:*:*:* OR *cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:* versions up to (including) 2.6.2
    Changed CPE Configuration OR *cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:* *cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:* *cpe:2.3:o:canonical:ubuntu_linux:15.10:*:*:*:*:*:*:* *cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* OR *cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:esm:*:*:* *cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:* *cpe:2.3:o:canonical:ubuntu_linux:15.10:*:*:*:*:*:*:* *cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
    Added CPE Configuration OR *cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
    Added CPE Configuration OR *cpe:2.3:a:redhat:openstack:6.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:openstack:7.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:openstack:8.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:openstack:9.0:*:*:*:*:*:*:* *cpe:2.3:a:redhat:openstack:10:*:*:*:*:*:*:* *cpe:2.3:a:redhat:openstack:11.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_eus:7.4:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_eus:7.5:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_eus:7.6:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_eus:7.7:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_server_aus:7.4:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_server_aus:7.7:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_server_tus:7.6:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_server_tus:7.7:*:*:*:*:*:*:* *cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:a:redhat:virtualization:4.0:*:*:*:*:*:*:* OR cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Dec. 01, 2018

    Action Type Old Value New Value
    Added Reference https://lists.debian.org/debian-lts-announce/2018/11/msg00038.html [No Types Assigned]
  • CVE Modified by [email protected]

    Jan. 05, 2018

    Action Type Old Value New Value
    Added Reference https://access.redhat.com/errata/RHSA-2017:2408 [No Types Assigned]
    Added Reference https://access.redhat.com/errata/RHSA-2017:2392 [No Types Assigned]
    Added Reference https://access.redhat.com/errata/RHSA-2017:1856 [No Types Assigned]
  • CVE Modified by [email protected]

    Jul. 01, 2017

    Action Type Old Value New Value
    Added Reference https://security.gentoo.org/glsa/201609-01 [No Types Assigned]
  • CVE Modified by [email protected]

    Nov. 28, 2016

    Action Type Old Value New Value
    Added Reference http://www.securityfocus.com/bid/86067 [No Types Assigned]
  • Modified Analysis by [email protected]

    Jun. 21, 2016

    Action Type Old Value New Value
    Changed CPE Configuration Configuration 1 OR *cpe:2.3:a:qemu:qemu:-:*:*:*:*:*:*:* Configuration 1 OR *cpe:2.3:a:qemu:qemu:-:*:*:*:*:*:*:* Configuration 2 OR *cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* *cpe:2.3:o:canonical:ubuntu_linux:15.10:*:*:*:*:*:*:* *cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:* *cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:*
  • CVE Modified by [email protected]

    Jun. 21, 2016

    Action Type Old Value New Value
    Added Reference http://www.ubuntu.com/usn/USN-2974-1
  • CVE Translated by [email protected]

    May. 29, 2016

    Action Type Old Value New Value
    Removed Translation La función patch_instruction en hw/i386/kvmvapic.c en QEMU no inicializa la variable imm32, lo que permite a administradores locales del SO invitado obtener información sensible de la memoria de pila del anfitrión accediendo a Task Priorty Register (TPR).
    Added Translation La función patch_instruction en hw/i386/kvmvapic.c en QEMU no inicializa la variable imm32, lo que permite a administradores locales del SO invitado obtener información sensible de la memoria de pila del anfitrión accediendo al Task Priority Register (TPR).
  • CVE Modified by [email protected]

    May. 29, 2016

    Action Type Old Value New Value
    Changed Description The patch_instruction function in hw/i386/kvmvapic.c in QEMU does not initialize the imm32 variable, which allows local guest OS administrators to obtain sensitive information from host stack memory by accessing the Task Priorty Register (TPR). The patch_instruction function in hw/i386/kvmvapic.c in QEMU does not initialize the imm32 variable, which allows local guest OS administrators to obtain sensitive information from host stack memory by accessing the Task Priority Register (TPR).
  • Modified Analysis by [email protected]

    May. 25, 2016

    Action Type Old Value New Value
    Added CPE Configuration Configuration 1 OR *cpe:2.3:a:qemu:qemu:-:*:*:*:*:*:*:*
    Added CVSS V2 (AV:L/AC:L/Au:N/C:P/I:N/A:N)
    Added CVSS V3 AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
    Changed Reference Type http://git.qemu.org/?p=qemu.git;a=commit;h=691a02e2ce0c413236a78dee6f2651c937b09fb0 No Types Assigned http://git.qemu.org/?p=qemu.git;a=commit;h=691a02e2ce0c413236a78dee6f2651c937b09fb0 Advisory
    Changed Reference Type https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg01106.html No Types Assigned https://lists.gnu.org/archive/html/qemu-devel/2016-04/msg01106.html Advisory
    Added CWE CWE-200
  • Initial Analysis by [email protected]

    May. 25, 2016

    Action Type Old Value New Value
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2016-4020 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2016-4020 weaknesses.

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.06 }} 0.00%

score

0.23061

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability