🛡️ CVE-2026-46048 — kernel

ALSA: caiaq: fix usb_dev refcount leak on probe failure

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

ALSA: caiaq: fix usb_dev refcount leak on probe failure

create_card() takes a reference on the USB device with usb_get_dev()

and stores the matching usb_put_dev() in card_free(), which is

installed as the snd_card's ->private_free destructor.

However, ->private_free is only assigned near the end of init_card(),

after several failure points (usb_set_interface(), EP type checks,

usb_submit_urb(), the EP1_CMD_GET_DEVICE_INFO exchange, and its

timeout). When any of those fail, init_card() returns an error to

snd_probe(), which calls snd_card_free(card). Because ->private_free

is still NULL, card_free() never runs, the usb_get_dev() reference

is not dropped, and the struct usb_device leaks along with its

descriptor allocations and device_private.

syzbot reproduces this with a malformed UAC3 device whose only valid

altsetting is 0; init_card()'s usb_set_interface(usb_dev, 0, 1) call

fails with -EIO and triggers the leak.

Move the ->private_free assignment into create_card(), immediately

after usb_get_dev(), so that every error path reaching snd_card_free()

balances the reference. card_free()'s callees (snd_usb_caiaq_input_free,

free_urbs, kfree) already tolerate the partially-initialized state

because the chip private area is zero-initialized by snd_card_new().