{"id":"CVE-2026-80854","state":"PUBLISHED","title":"usb: gadget: f_tcm: keep port count until LUN teardown completes","description":"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.","publishedAt":"2026-09-04T15:55:06.478Z","updatedAt":"2026-10-19T08:44:48.320Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"c494c5562ca69b61a82f566e3b87a445d2c28929","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"c1f359d9a5efed458946063de65ddbeaacc4f165","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"178f59a0bccd3f66cdfa5184310f31a58b7257c4","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"ad6f0375d2e93a1d8c015463e5e92dfcb26e311b","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"2efbfd42441d3ef8137aff2d59e9835e1d5ae780","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"85aa61fedcb4eb13f3dc5db73f6dc359f41f5d95","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"bbd6aa311a9f4dd17822c7557451458d3d2e980b","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"eaa96a8458f54d6cf0954242ab8b1df2a6fccafa","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"c39d0916da47d94909391876c9e5bd429ea7b1b9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/target/target_core_fabric_configfs.c","drivers/usb/gadget/function/f_tcm.c","include/target/target_core_fabric.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.5","versionType":"semver"},{"version":"5.10.269","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.220","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.187","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.156","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.108","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.49","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.13","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2.3","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/target/target_core_fabric_configfs.c","drivers/usb/gadget/function/f_tcm.c","include/target/target_core_fabric.h"]}],"references":["https://git.kernel.org/stable/c/c494c5562ca69b61a82f566e3b87a445d2c28929","https://git.kernel.org/stable/c/c1f359d9a5efed458946063de65ddbeaacc4f165","https://git.kernel.org/stable/c/178f59a0bccd3f66cdfa5184310f31a58b7257c4","https://git.kernel.org/stable/c/ad6f0375d2e93a1d8c015463e5e92dfcb26e311b","https://git.kernel.org/stable/c/2efbfd42441d3ef8137aff2d59e9835e1d5ae780","https://git.kernel.org/stable/c/85aa61fedcb4eb13f3dc5db73f6dc359f41f5d95","https://git.kernel.org/stable/c/bbd6aa311a9f4dd17822c7557451458d3d2e980b","https://git.kernel.org/stable/c/eaa96a8458f54d6cf0954242ab8b1df2a6fccafa","https://git.kernel.org/stable/c/c39d0916da47d94909391876c9e5bd429ea7b1b9"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/80xxx/CVE-2026-80854.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80854","state":"PUBLISHED","datePublished":"2026-09-04T15:55:06.478Z","dateUpdated":"2026-10-19T08:44:48.320Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-26T14:34:25.797Z"},"containers":{"cna":{"title":"usb: gadget: f_tcm: keep port count until LUN teardown completes","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"c494c5562ca69b61a82f566e3b87a445d2c28929","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"c1f359d9a5efed458946063de65ddbeaacc4f165","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"178f59a0bccd3f66cdfa5184310f31a58b7257c4","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"ad6f0375d2e93a1d8c015463e5e92dfcb26e311b","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"2efbfd42441d3ef8137aff2d59e9835e1d5ae780","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"85aa61fedcb4eb13f3dc5db73f6dc359f41f5d95","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"bbd6aa311a9f4dd17822c7557451458d3d2e980b","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"eaa96a8458f54d6cf0954242ab8b1df2a6fccafa","versionType":"git"},{"version":"c52661d60f636d17e26ad834457db333bd1df494","status":"affected","lessThan":"c39d0916da47d94909391876c9e5bd429ea7b1b9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/target/target_core_fabric_configfs.c","drivers/usb/gadget/function/f_tcm.c","include/target/target_core_fabric.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.5","versionType":"semver"},{"version":"5.10.269","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.220","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.187","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.156","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.108","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.49","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.13","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2.3","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/target/target_core_fabric_configfs.c","drivers/usb/gadget/function/f_tcm.c","include/target/target_core_fabric.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/c494c5562ca69b61a82f566e3b87a445d2c28929"},{"url":"https://git.kernel.org/stable/c/c1f359d9a5efed458946063de65ddbeaacc4f165"},{"url":"https://git.kernel.org/stable/c/178f59a0bccd3f66cdfa5184310f31a58b7257c4"},{"url":"https://git.kernel.org/stable/c/ad6f0375d2e93a1d8c015463e5e92dfcb26e311b"},{"url":"https://git.kernel.org/stable/c/2efbfd42441d3ef8137aff2d59e9835e1d5ae780"},{"url":"https://git.kernel.org/stable/c/85aa61fedcb4eb13f3dc5db73f6dc359f41f5d95"},{"url":"https://git.kernel.org/stable/c/bbd6aa311a9f4dd17822c7557451458d3d2e980b"},{"url":"https://git.kernel.org/stable/c/eaa96a8458f54d6cf0954242ab8b1df2a6fccafa"},{"url":"https://git.kernel.org/stable/c/c39d0916da47d94909391876c9e5bd429ea7b1b9"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:44:48.320Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"5.10.269"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"5.15.220"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.1.187"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.6.156"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.12.108"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.18.49"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"7.1.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"7.2.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