CVE-2016-4020

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    CVE-2016-4020

    Published: 25 May 2016Last Modified: 8 Jul 2026

    Summary:

    Details: 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).

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

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    v2.6.2
    v2.6.1
    v2.6.0
    v2.6.0-rc5
    v2.6.0-rc4
    v2.6.0-rc3
    v2.6.0-rc2
    v2.6.0-rc1
    v2.6.0-rc0

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High