CVE-2026-80854

    Dashboard / Vulnerabilities / CVE-2026-80854

    CVE-2026-80854

    Published: 4 Sept 2026Last Modified: 15 Sept 2026

    Summary: usb: gadget: f_tcm: keep port count until LUN teardown completes

    Details: In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_tcm: keep port count until LUN teardown completes tcm_usbg_drop_nexus() permits session removal once tpg_port_count reaches zero. However, usbg_port_unlink() currently decrements that count from the fabric_pre_unlink() callback, before core_dev_del_lun() waits for active se_lun references to drain. If removal of the last LUN races a nexus removal, the latter can observe a zero port count and call target_remove_session(). This frees sess_cmd_map while an in-flight struct usbg_cmd, including its work item, can still be accessed. Overlapping the last-LUN unlink with nexus removal reproduces this lifetime violation as a DEBUG_OBJECTS "free active" warning for usbg_cmd_work, followed by a target-core BUG/Oops. The generic target-core unlink path has no callback after core_dev_del_lun() completes. Add an optional fabric_post_unlink() callback and use it for the f_tcm port count. The count now remains nonzero until core_dev_del_lun() has finished draining active LUN references, preventing nexus removal from freeing the session during command completion.

    References: https://git.kernel.org/stable/c/178f59a0bccd3f66cdfa5184310f31a58b7257c4, https://git.kernel.org/stable/c/2efbfd42441d3ef8137aff2d59e9835e1d5ae780, https://git.kernel.org/stable/c/85aa61fedcb4eb13f3dc5db73f6dc359f41f5d95, https://git.kernel.org/stable/c/ad6f0375d2e93a1d8c015463e5e92dfcb26e311b, https://git.kernel.org/stable/c/bbd6aa311a9f4dd17822c7557451458d3d2e980b, https://git.kernel.org/stable/c/c1f359d9a5efed458946063de65ddbeaacc4f165, https://git.kernel.org/stable/c/c39d0916da47d94909391876c9e5bd429ea7b1b9, https://git.kernel.org/stable/c/c494c5562ca69b61a82f566e3b87a445d2c28929, https://git.kernel.org/stable/c/eaa96a8458f54d6cf0954242ab8b1df2a6fccafa, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80854.json, https://nvd.nist.gov/vuln/detail/CVE-2026-80854, https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- c52661d60f636d17e26ad834457db333bd1df494
    Fixed -c494c5562ca69b61a82f566e3b87a445d2c28929

    Affected versions

    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-2026-80854 | CVE-DB