CVE-2025-21776

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

USB: hub: Ignore non-compliant devices with too many configs or interfaces

Robert Morris created a test program which can cause

usb_hub_to_struct_hub() to dereference a NULL or inappropriate

pointer:

Oops: general protection fault, probably for non-canonical address

0xcccccccccccccccc: 0000 [#1] SMP DEBUG_PAGEALLOC PTI

CPU: 7 UID: 0 PID: 117 Comm: kworker/7:1 Not tainted 6.13.0-rc3-00017-gf44d154d6e3d #14

Hardware name: FreeBSD BHYVE/BHYVE, BIOS 14.0 10/17/2021

Workqueue: usb_hub_wq hub_event

RIP: 0010:usb_hub_adjust_deviceremovable+0x78/0x110

...

Call Trace:

<TASK>

? die_addr+0x31/0x80

? exc_general_protection+0x1b4/0x3c0

? asm_exc_general_protection+0x26/0x30

? usb_hub_adjust_deviceremovable+0x78/0x110

hub_probe+0x7c7/0xab0

usb_probe_interface+0x14b/0x350

really_probe+0xd0/0x2d0

? __pfx___device_attach_driver+0x10/0x10

__driver_probe_device+0x6e/0x110

driver_probe_device+0x1a/0x90

__device_attach_driver+0x7e/0xc0

bus_for_each_drv+0x7f/0xd0

__device_attach+0xaa/0x1a0

bus_probe_device+0x8b/0xa0

device_add+0x62e/0x810

usb_set_configuration+0x65d/0x990

usb_generic_driver_probe+0x4b/0x70

usb_probe_device+0x36/0xd0

The cause of this error is that the device has two interfaces, and the

hub driver binds to interface 1 instead of interface 0, which is where

usb_hub_to_struct_hub() looks.

We can prevent the problem from occurring by refusing to accept hub

devices that violate the USB spec by having more than one

configuration or interface.