CVE-2023-4208

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    CVE-2023-4208

    Published: 6 Sept 2023Last Modified: 12 Aug 2026

    Summary: Use-after-free in Linux kernel's net/sched: cls_u32 component

    Details: A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component can be exploited to achieve local privilege escalation. When u32_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free. We recommend upgrading past commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81.

    References: https://git.kernel.org, https://kernel.dance/3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81, https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html, https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/4xxx/CVE-2023-4208.json, https://nvd.nist.gov/vuln/detail/CVE-2023-4208, https://www.debian.org/security/2023/dsa-5492, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- b2776bf7149bddd1f4161f14f79520f17fc1d71d
    Fixed -2dde18cd1d8fac735875f2e4987f11817cc0bc2c

    Affected versions

    v6.5-rc1

    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
    CVE-2023-4208 | CVE-DB