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 gadgets 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 gadgets release routine.

Affected Software

References

• https://git.kernel.org/stable/c/50eeb8e8a4f389efc91b93cff14a683e714ec194
• https://git.kernel.org/stable/c/54fa390aae393eb130f307a85562e3001cc39a52
• https://git.kernel.org/stable/c/67e511d2989eb1c8c588b599ce2fcc6bb8e6f7ea
• https://git.kernel.org/stable/c/7a5214dae906d9f58e07bc4995e8181ee74439f4
• https://git.kernel.org/stable/c/b52476a83d9e12df00765359d728a875b128bef1
• https://git.kernel.org/stable/c/d026f71df141c9b064ff32a78af5391a31ef75c2