Upstream information

CVE-2026-31721 at MITRE

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.

SUSE information

Overall state of this security issue: Does not affect SUSE products

SUSE Bugzilla entry: 1264117 [RESOLVED / FIXED]

No SUSE Security Announcements cross referenced.


SUSE Timeline for this CVE

CVE page created: Tue May 5 17:23:41 2026
CVE page last modified: Fri May 8 12:08:52 2026