{"api_version":"1","generated_at":"2026-07-07T04:13:36+00:00","cve":"CVE-2026-31721","urls":{"html":"https://cve.report/CVE-2026-31721","api":"https://cve.report/api/cve/CVE-2026-31721.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-31721","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-31721"},"summary":{"title":"usb: gadget: f_hid: move list and spinlock inits from bind to alloc","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_hid: move list and spinlock inits from bind to alloc\n\nThere was an issue when you did the following:\n- setup and bind an hid gadget\n- open /dev/hidg0\n- use the resulting fd in EPOLL_CTL_ADD\n- unbind the UDC\n- bind the UDC\n- use the fd in EPOLL_CTL_DEL\n\nWhen CONFIG_DEBUG_LIST was enabled, a list_del corruption was reported\nwithin remove_wait_queue (via ep_remove_wait_queue). After some\ndebugging I found out that the queues, which f_hid registers via\npoll_wait were the problem. These were initialized using\ninit_waitqueue_head inside hidg_bind. So effectively, the bind function\nre-initialized the queues while there were still items in them.\n\nThe solution is to move the initialization from hidg_bind to hidg_alloc\nto extend their lifetimes to the lifetime of the function instance.\n\nAdditionally, I found many other possibly problematic init calls in the\nbind function, which I moved as well.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-01 15:16:34","updated_at":"2026-05-06 20:56:34"},"problem_types":["NVD-CWE-noinfo"],"metrics":[{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"5.5","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}}],"references":[{"url":"https://git.kernel.org/stable/c/26a879a41ed960b3fb4ec773ef2788c515c0e488","name":"https://git.kernel.org/stable/c/26a879a41ed960b3fb4ec773ef2788c515c0e488","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/de93e0862169b5539e00c2b9980b93fd80c37c0d","name":"https://git.kernel.org/stable/c/de93e0862169b5539e00c2b9980b93fd80c37c0d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4e0a88254ad59f6c53a34bf5fa241884ec09e8b2","name":"https://git.kernel.org/stable/c/4e0a88254ad59f6c53a34bf5fa241884ec09e8b2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/81aee4500055876883658b024b6fb61801afe134","name":"https://git.kernel.org/stable/c/81aee4500055876883658b024b6fb61801afe134","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8ec6a58586f195a88479edcdb0b8027c39f12d03","name":"https://git.kernel.org/stable/c/8ec6a58586f195a88479edcdb0b8027c39f12d03","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f7d00ee1c8082c8a134340aaf16d71a27e29c362","name":"https://git.kernel.org/stable/c/f7d00ee1c8082c8a134340aaf16d71a27e29c362","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5d1bb391ceeebb28327703dd07af8c6324af298f","name":"https://git.kernel.org/stable/c/5d1bb391ceeebb28327703dd07af8c6324af298f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/13440c0db227c5db01da751ed966dde4cdd2ea18","name":"https://git.kernel.org/stable/c/13440c0db227c5db01da751ed966dde4cdd2ea18","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-31721","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31721","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cb382536052fcc7713988869b54a81137069e5a9 13440c0db227c5db01da751ed966dde4cdd2ea18 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cb382536052fcc7713988869b54a81137069e5a9 de93e0862169b5539e00c2b9980b93fd80c37c0d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cb382536052fcc7713988869b54a81137069e5a9 81aee4500055876883658b024b6fb61801afe134 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected cb382536052fcc7713988869b54a81137069e5a9 8ec6a58586f195a88479edcdb0b8027c39f12d03 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_hid: move list and spinlock inits from bind to alloc\n\nThere was an issue when you did the following:\n- setup and bind an hid gadget\n- open /dev/hidg0\n- use the resulting fd in EPOLL_CTL_ADD\n- unbind the UDC\n- bind the UDC\n- use the fd in EPOLL_CTL_DEL\n\nWhen CONFIG_DEBUG_LIST was enabled, a list_del corruption was reported\nwithin remove_wait_queue (via ep_remove_wait_queue). After some\ndebugging I found out that the queues, which f_hid registers via\npoll_wait were the problem. These were initialized using\ninit_waitqueue_head inside hidg_bind. So effectively, the bind function\nre-initialized the queues while there were still items in them.\n\nThe solution is to move the initialization from hidg_bind to hidg_alloc\nto extend their lifetimes to the lifetime of the function instance.\n\nAdditionally, I found many other possibly problematic init calls in the\nbind function, which I moved as well."}],"providerMetadata":{"dateUpdated":"2026-05-02T06:14:22.498Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/13440c0db227c5db01da751ed966dde4cdd2ea18"},{"url":"https://git.kernel.org/stable/c/de93e0862169b5539e00c2b9980b93fd80c37c0d"},{"url":"https://git.kernel.org/stable/c/81aee4500055876883658b024b6fb61801afe134"},{"url":"https://git.kernel.org/stable/c/8ec6a58586f195a88479edcdb0b8027c39f12d03"},{"url":"https://git.kernel.org/stable/c/f7d00ee1c8082c8a134340aaf16d71a27e29c362"},{"url":"https://git.kernel.org/stable/c/5d1bb391ceeebb28327703dd07af8c6324af298f"},{"url":"https://git.kernel.org/stable/c/26a879a41ed960b3fb4ec773ef2788c515c0e488"},{"url":"https://git.kernel.org/stable/c/4e0a88254ad59f6c53a34bf5fa241884ec09e8b2"}],"title":"usb: gadget: f_hid: move list and spinlock inits from bind to 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gadget: f_hid: move list and spinlock inits from bind to al","CVE":"CVE-2026-31721","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"31721","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_hid: move list and spinlock inits from bind to alloc\n\nThere was an issue when you did the following:\n- setup and bind an hid gadget\n- open /dev/hidg0\n- use the resulting fd in EPOLL_CTL_ADD\n- unbind the UDC\n- bind the UDC\n- use the fd in EPOLL_CTL_DEL\n\nWhen CONFIG_DEBUG_LIST was enabled, a list_del corruption was reported\nwithin remove_wait_queue (via ep_remove_wait_queue). After some\ndebugging I found out that the queues, which f_hid registers via\npoll_wait were the problem. These were initialized using\ninit_waitqueue_head inside hidg_bind. So effectively, the bind function\nre-initialized the queues while there were still items in them.\n\nThe solution is to move the initialization from hidg_bind to hidg_alloc\nto extend their lifetimes to the lifetime of the function instance.\n\nAdditionally, I found many other possibly problematic init calls in the\nbind function, which I moved as well.","Type":"Description","Title":"usb: gadget: f_hid: move list and spinlock inits from bind to al"}]}}}