CVE-2026-31721

Description

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_hid: move list and spinlock inits from bind to alloc There was an issue when you did the following: - setup and bind an hid gadget - open /dev/hidg0 - use the resulting fd in EPOLL_CTL_ADD - unbind the UDC - bind the UDC - use the fd in EPOLL_CTL_DEL When CONFIG_DEBUG_LIST was enabled, a list_del corruption was reported within remove_wait_queue (via ep_remove_wait_queue). After some debugging I found out that the queues, which f_hid registers via poll_wait were the problem. These were initialized using init_waitqueue_head inside hidg_bind. So effectively, the bind function re-initialized the queues while there were still items in them. The solution is to move the initialization from hidg_bind to hidg_alloc to extend their lifetimes to the lifetime of the function instance. Additionally, I found many other possibly problematic init calls in the bind function, which I moved as well.

PUBLISHED Reserved 2026-03-09 | Published 2026-05-01 | Updated 2026-05-02 | Assigner Linux

Product status

References

git.kernel.org/...c/13440c0db227c5db01da751ed966dde4cdd2ea18

git.kernel.org/...c/de93e0862169b5539e00c2b9980b93fd80c37c0d

git.kernel.org/...c/81aee4500055876883658b024b6fb61801afe134

git.kernel.org/...c/8ec6a58586f195a88479edcdb0b8027c39f12d03

git.kernel.org/...c/f7d00ee1c8082c8a134340aaf16d71a27e29c362

git.kernel.org/...c/5d1bb391ceeebb28327703dd07af8c6324af298f

git.kernel.org/...c/26a879a41ed960b3fb4ec773ef2788c515c0e488

git.kernel.org/...c/4e0a88254ad59f6c53a34bf5fa241884ec09e8b2

cve.org (CVE-2026-31721)

nvd.nist.gov (CVE-2026-31721)

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