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CVE-2026-31721

usb: gadget: f_hid: move list and spinlock inits from bind to alloc

EPSS 0.1%
Vexday Risk Score
3Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS EPSS 0.1%KEV nãoPoC Nuclei Metasploit Patch
Lifecycle
01 May 2026Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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.
Affected products
Linux · Linux

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