UBUNTU-CVE-2023-4623

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    UBUNTU-CVE-2023-4623

    Published: 6 Sept 2023Last Modified: 9 Sept 2026
    Upstream:
    CVE-2023-4623
    Aliases:
    USN-6415-1
    USN-6439-1
    USN-6439-2

    Summary:

    Details: A use-after-free vulnerability in the Linux kernel's net/sched: sch_hfsc (HFSC qdisc traffic control) component can be exploited to achieve local privilege escalation. If a class with a link-sharing curve (i.e. with the HFSC_FSC flag set) has a parent without a link-sharing curve, then init_vf() will call vttree_insert() on the parent, but vttree_remove() will be skipped in update_vf(). This leaves a dangling pointer that can cause a use-after-free. We recommend upgrading past commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f.

    References: https://ubuntu.com/security/CVE-2023-4623, https://git.kernel.org/linus/b3d26c5702c7d6c45456326e56d2ccf3f103e60f, https://kernel.dance/b3d26c5702c7d6c45456326e56d2ccf3f103e60f, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b3d26c5702c7d6c45456326e56d2ccf3f103e60f, https://ubuntu.com/security/notices/USN-6415-1, 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-6441-3, https://ubuntu.com/security/notices/USN-6460-1, https://ubuntu.com/security/notices/USN-6466-1, https://www.cve.org/CVERecord?id=CVE-2023-4623

    Affected packages

    Package

    Name: linux

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

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -3.13.0-194.245

    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-2023-4623 | CVE-DB