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CVE-2026-80854

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

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.269, 5.15.220, 6.1.187, 6.6.156, 6.12.108, and 3 more
None on Exploit-DB, Metasploit or GitHub

Summary

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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From c52661d60f636d17e26ad834457db333bd1df494 · fixed in c494c5562ca69b61a82f566e3b87a445d2c28929; From c52661d60f636d17e26ad834457db333bd1df494 · fixed in c1f359d9a5efed458946063de65ddbeaacc4f165; From c52661d60f636d17e26ad834457db333bd1df494 · fixed in 178f59a0bccd3f66cdfa5184310f31a58b7257c4; From c52661d60f636d17e26ad834457db333bd1df494 · fixed in ad6f0375d2e93a1d8c015463e5e92dfcb26e311b; From c52661d60f636d17e26ad834457db333bd1df494 · fixed in 2efbfd42441d3ef8137aff2d59e9835e1d5ae780; From c52661d60f636d17e26ad834457db333bd1df494 · fixed in 85aa61fedcb4eb13f3dc5db73f6dc359f41f5d95; From c52661d60f636d17e26ad834457db333bd1df494 · fixed in bbd6aa311a9f4dd17822c7557451458d3d2e980b; From c52661d60f636d17e26ad834457db333bd1df494 · fixed in eaa96a8458f54d6cf0954242ab8b1df2a6fccafa; From c52661d60f636d17e26ad834457db333bd1df494 · fixed in c39d0916da47d94909391876c9e5bd429ea7b1b9

  • Linux Linux

    3.5

  • KernelLinux

    From 3.5.0 · fixed in 5.10.269; From 5.11.0 · fixed in 5.15.220; From 5.16.0 · fixed in 6.1.187; From 6.2.0 · fixed in 6.6.156; From 6.7.0 · fixed in 6.12.108; From 6.13.0 · fixed in 6.18.49; From 6.19.0 · fixed in 7.1.13; From 7.2.0 · fixed in 7.2.3

References 9

git.kernel.org