CVE-2026-31721: Linux kernel · usb: gadget: f_hid: move list and spinlock inits from bind to alloc
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 11 Nov 2026, 23:24 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 1 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.
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.
References
- git.kernel.org/stable/c/13440c0db227c5db01da751ed966dde4cdd2ea18 (opens in a new tab)
- git.kernel.org/stable/c/de93e0862169b5539e00c2b9980b93fd80c37c0d (opens in a new tab)
- git.kernel.org/stable/c/81aee4500055876883658b024b6fb61801afe134 (opens in a new tab)
- git.kernel.org/stable/c/8ec6a58586f195a88479edcdb0b8027c39f12d03 (opens in a new tab)
- git.kernel.org/stable/c/f7d00ee1c8082c8a134340aaf16d71a27e29c362 (opens in a new tab)
- git.kernel.org/stable/c/5d1bb391ceeebb28327703dd07af8c6324af298f (opens in a new tab)
- git.kernel.org/stable/c/26a879a41ed960b3fb4ec773ef2788c515c0e488 (opens in a new tab)
- git.kernel.org/stable/c/4e0a88254ad59f6c53a34bf5fa241884ec09e8b2 (opens in a new tab)