{"cve":"CVE-2026-31721","nvd":{"published":"2026-05-01T15:16:34.490","modified":"2026-06-17T10:34:18.503","status":"Analyzed","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/13440c0db227c5db01da751ed966dde4cdd2ea18","https://git.kernel.org/stable/c/26a879a41ed960b3fb4ec773ef2788c515c0e488","https://git.kernel.org/stable/c/4e0a88254ad59f6c53a34bf5fa241884ec09e8b2","https://git.kernel.org/stable/c/5d1bb391ceeebb28327703dd07af8c6324af298f","https://git.kernel.org/stable/c/81aee4500055876883658b024b6fb61801afe134"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:33:09.003606135+00:00"},"epss":{"cve":"CVE-2026-31721","score":0.00127,"percentile":0.02367,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}