CVE-2026-46048ALSA: caiaq: fix usb_dev refcount leak on probe failure

Official description

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().

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/c874db8a1d2f9f08161470d00cfe8db2f5cca2cc
• https://git.kernel.org/stable/c/6fa8dff64fb6c401ced40a05797b327659317498
• https://git.kernel.org/stable/c/a8d907acc3e5a078c2e5637ff60c30c6d2ddc23a
• https://git.kernel.org/stable/c/50c6a1f05973f56d23280c9d7645a7a5734e0907
• https://git.kernel.org/stable/c/da3b8fd6a202d94fef11a443abc9171c52426a1c
• https://git.kernel.org/stable/c/6153878c5255bb69b7d0868105ca078ef13cbcf8
• https://git.kernel.org/stable/c/21ca595aafa40d3ac70eab1f4cb62cc00ca21657
• https://git.kernel.org/stable/c/7a5f1cd22d47f8ca4b760b6334378ae42c1bd24b