Bug 2482119 (CVE-2026-46048)

Summary: CVE-2026-46048 kernel: ALSA: caiaq: fix usb_dev refcount leak on probe failure
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's ALSA caiaq driver. This vulnerability, a reference count leak, occurs when the `create_card()` function acquires a reference to a USB device, but the corresponding release is not performed if `init_card()` fails before the destructor is properly assigned. A local attacker with a malformed Universal Audio Class 3 (UAC3) device could exploit this to cause a resource leak, potentially leading to a denial of service due to system resource exhaustion.
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Description OSIDB Bzimport 2026-05-27 15:12:13 UTC 
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().
Comment 1 Keith Grant 2026-05-27 19:19:29 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052753-CVE-2026-46048-f25e@gregkh/T