UBUNTU-CVE-2021-3748

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    UBUNTU-CVE-2021-3748

    Published: 31 Aug 2021Last Modified: 4 Feb 2026
    Upstream:
    CVE-2021-3748
    Aliases:
    USN-5307-1

    Summary:

    Details: A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor's address belongs to the non direct access region, due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU, resulting in a denial of service condition, or potentially execute code on the host with the privileges of the QEMU process.

    References: https://ubuntu.com/security/CVE-2021-3748, https://lists.nongnu.org/archive/html/qemu-devel/2021-09/msg00388.html, https://ubuntu.com/security/notices/USN-5307-1, https://www.cve.org/CVERecord?id=CVE-2021-3748

    Affected packages

    Package

    Name: qemu

    Purl: pkg:deb/ubuntu/qemu@1:2.11+dfsg-1ubuntu7.39?arch=source&distro=bionic

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -1:2.11+dfsg-1ubuntu7.39

    Affected versions

    1:2.10+dfsg-0ubuntu3

    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-2021-3748 | CVE-DB