{"id":"CVE-2026-80854","summary":"usb: gadget: f_tcm: keep port count until LUN teardown completes","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_tcm: keep port count until LUN teardown completes\n\ntcm_usbg_drop_nexus() permits session removal once tpg_port_count\nreaches zero. However, usbg_port_unlink() currently decrements that\ncount from the fabric_pre_unlink() callback, before core_dev_del_lun()\nwaits for active se_lun references to drain.\n\nIf removal of the last LUN races a nexus removal, the latter can observe\na zero port count and call target_remove_session(). This frees\nsess_cmd_map while an in-flight struct usbg_cmd, including its work item,\ncan still be accessed.\n\nOverlapping the last-LUN unlink with nexus removal reproduces this\nlifetime violation as a DEBUG_OBJECTS \"free active\" warning for\nusbg_cmd_work, followed by a target-core BUG/Oops.\n\nThe generic target-core unlink path has no callback after\ncore_dev_del_lun() completes. Add an optional fabric_post_unlink()\ncallback and use it for the f_tcm port count. The count now remains\nnonzero until core_dev_del_lun() has finished draining active LUN\nreferences, preventing nexus removal from freeing the session during\ncommand completion.","modified":"2026-09-06T03:46:53.985871116Z","published":"2026-09-04T15:55:06.478Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80854.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/178f59a0bccd3f66cdfa5184310f31a58b7257c4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2efbfd42441d3ef8137aff2d59e9835e1d5ae780"},{"type":"WEB","url":"https://git.kernel.org/stable/c/85aa61fedcb4eb13f3dc5db73f6dc359f41f5d95"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ad6f0375d2e93a1d8c015463e5e92dfcb26e311b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bbd6aa311a9f4dd17822c7557451458d3d2e980b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c1f359d9a5efed458946063de65ddbeaacc4f165"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c39d0916da47d94909391876c9e5bd429ea7b1b9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c494c5562ca69b61a82f566e3b87a445d2c28929"},{"type":"WEB","url":"https://git.kernel.org/stable/c/eaa96a8458f54d6cf0954242ab8b1df2a6fccafa"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80854.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80854"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c52661d60f636d17e26ad834457db333bd1df494"},{"fixed":"c494c5562ca69b61a82f566e3b87a445d2c28929"},{"fixed":"c1f359d9a5efed458946063de65ddbeaacc4f165"},{"fixed":"178f59a0bccd3f66cdfa5184310f31a58b7257c4"},{"fixed":"ad6f0375d2e93a1d8c015463e5e92dfcb26e311b"},{"fixed":"2efbfd42441d3ef8137aff2d59e9835e1d5ae780"},{"fixed":"85aa61fedcb4eb13f3dc5db73f6dc359f41f5d95"},{"fixed":"bbd6aa311a9f4dd17822c7557451458d3d2e980b"},{"fixed":"eaa96a8458f54d6cf0954242ab8b1df2a6fccafa"},{"fixed":"c39d0916da47d94909391876c9e5bd429ea7b1b9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80854.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.5.0"},{"fixed":"5.10.269"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.220"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.187"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.156"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.108"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.49"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.13"}]},{"type":"ECOSYSTEM","events":[{"introduced":"7.2.0"},{"fixed":"7.2.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80854.json"}}],"schema_version":"1.9.0"}