UBUNTU-CVE-2023-4921

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    UBUNTU-CVE-2023-4921

    Published: 12 Sept 2023Last Modified: 5 Oct 2026
    Upstream:
    CVE-2023-4921
    Aliases:
    USN-6439-1
    USN-6439-2
    USN-6440-1

    Summary:

    Details: A use-after-free vulnerability in the Linux kernel's net/sched: sch_qfq component can be exploited to achieve local privilege escalation. When the plug qdisc is used as a class of the qfq qdisc, sending network packets triggers use-after-free in qfq_dequeue() due to the incorrect .peek handler of sch_plug and lack of error checking in agg_dequeue(). We recommend upgrading past commit 8fc134fee27f2263988ae38920bc03da416b03d8.

    References: https://ubuntu.com/security/CVE-2023-4921, https://lore.kernel.org/all/[email protected]/, https://ubuntu.com/security/notices/USN-6439-1, https://ubuntu.com/security/notices/USN-6440-1, https://ubuntu.com/security/notices/USN-6441-1, https://ubuntu.com/security/notices/USN-6442-1, https://ubuntu.com/security/notices/USN-6444-1, https://ubuntu.com/security/notices/USN-6445-1, https://ubuntu.com/security/notices/USN-6446-1, https://ubuntu.com/security/notices/USN-6440-2, https://ubuntu.com/security/notices/USN-6439-2, https://ubuntu.com/security/notices/USN-6441-2, https://ubuntu.com/security/notices/USN-6444-2, https://ubuntu.com/security/notices/USN-6445-2, https://ubuntu.com/security/notices/USN-6446-2, https://ubuntu.com/security/notices/USN-6440-3, https://ubuntu.com/security/notices/USN-6446-3, https://ubuntu.com/security/notices/USN-6454-1, https://ubuntu.com/security/notices/USN-6441-3, https://ubuntu.com/security/notices/USN-6454-2, https://ubuntu.com/security/notices/USN-6461-1, https://ubuntu.com/security/notices/USN-6466-1, https://ubuntu.com/security/notices/USN-6454-3, https://ubuntu.com/security/notices/USN-6454-4, https://ubuntu.com/security/notices/USN-6479-1, https://ubuntu.com/security/notices/USN-6699-1, https://www.cve.org/CVERecord?id=CVE-2023-4921

    Affected packages

    Package

    Name: linux

    Purl: pkg:deb/ubuntu/linux?arch=source&distro=trusty%2Fesm

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -3.13.0-197.248

    Affected versions

    3.11.0-12.19

    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-2023-4921 | CVE-DB