CVE-2026-64346

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: udc: Fix use-after-free in gadget_match_driver

The udc structure acts as the management structure for the gadget,

but their lifecycles are decoupled. A race condition exists where

usb_del_gadget() frees the udc memory (e.g., via mode-switch work)

while gadget_match_driver() concurrently accesses the freed udc memory

(e.g., via configfs), causing a Use-After-Free (UAF) that triggers a

NULL pointer dereference when the freed memory is zeroed:

[39430.908615][ T1171] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000

[39430.911397][ T1171] pc : __pi_strcmp+0x20/0x140

[39430.911441][ T1171] lr : gadget_match_driver+0x34/0x60

...

[39430.911890][ T1171] usb_gadget_register_driver_owner+0x50/0xf8

[39430.911910][ T1171] gadget_dev_desc_UDC_store+0xf4/0x140

[39430.931308][ T1171] configfs_write_iter+0xec/0x134

[39430.957058][ T1171] Workqueue: events_freezable __dwc3_set_mode

[39430.957287][ T1171] dwc3_gadget_exit+0x34/0x8c

[39430.957304][ T1171] __dwc3_set_mode+0xc0/0x664

Fix this by ensuring the udc structure remains allocated until the

gadget is released. To achieve this, introduce a new

usb_gadget_release() routine to the core. When the gadget is added,

usb_add_gadget() stores the gadget's release routine in the udc

structure and takes a reference to the udc. When the gadget is

released, usb_gadget_release() drops the reference to the udc and

then calls the gadget's release routine.