{"id":"CVE-2026-31721","summary":"usb: gadget: f_hid: move list and spinlock inits from bind to alloc","details":"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.","modified":"2026-05-18T05:59:54.371383067Z","published":"2026-05-01T14:14:23.492Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31721.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/13440c0db227c5db01da751ed966dde4cdd2ea18"},{"type":"WEB","url":"https://git.kernel.org/stable/c/26a879a41ed960b3fb4ec773ef2788c515c0e488"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4e0a88254ad59f6c53a34bf5fa241884ec09e8b2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5d1bb391ceeebb28327703dd07af8c6324af298f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/81aee4500055876883658b024b6fb61801afe134"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8ec6a58586f195a88479edcdb0b8027c39f12d03"},{"type":"WEB","url":"https://git.kernel.org/stable/c/de93e0862169b5539e00c2b9980b93fd80c37c0d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f7d00ee1c8082c8a134340aaf16d71a27e29c362"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31721.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31721"},{"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":"cb382536052fcc7713988869b54a81137069e5a9"},{"fixed":"13440c0db227c5db01da751ed966dde4cdd2ea18"},{"fixed":"de93e0862169b5539e00c2b9980b93fd80c37c0d"},{"fixed":"81aee4500055876883658b024b6fb61801afe134"},{"fixed":"8ec6a58586f195a88479edcdb0b8027c39f12d03"},{"fixed":"f7d00ee1c8082c8a134340aaf16d71a27e29c362"},{"fixed":"5d1bb391ceeebb28327703dd07af8c6324af298f"},{"fixed":"26a879a41ed960b3fb4ec773ef2788c515c0e488"},{"fixed":"4e0a88254ad59f6c53a34bf5fa241884ec09e8b2"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31721.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.19.0"},{"fixed":"5.10.253"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.203"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.169"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.135"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.81"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.22"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.12"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-31721.json"}}],"schema_version":"1.7.5"}