UBUNTU-CVE-2021-4093

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    UBUNTU-CVE-2021-4093

    Published: 13 Dec 2021Last Modified: 4 Feb 2026
    Upstream:
    CVE-2021-4093
    Aliases:
    USN-5265-1

    Summary:

    Details: A flaw was found in the KVM's AMD code for supporting the Secure Encrypted Virtualization-Encrypted State (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kernel via a malicious VMGEXIT for a string I/O instruction (for example, outs or ins) using the exit reason SVM_EXIT_IOIO. This issue results in a crash of the entire system or a potential guest-to-host escape scenario.

    References: https://ubuntu.com/security/CVE-2021-4093, https://git.kernel.org/linus/95e16b4792b0429f1933872f743410f00e590c55, https://ubuntu.com/security/notices/USN-5265-1, https://www.cve.org/CVERecord?id=CVE-2021-4093

    Affected packages

    Package

    Name: linux-hwe-edge

    Purl: pkg:deb/ubuntu/[email protected]~16.04.1?arch=source&distro=xenial

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    4.8.0-28.30~16.04.1
    4.8.0-30.32~16.04.1
    4.8.0-32.34~16.04.1
    4.8.0-34.36~16.04.1

    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
    UBUNTU-CVE-2021-4093 | CVE-DB