Bug 2461471 (CVE-2026-31581)

Summary: CVE-2026-31581 kernel: ALSA: 6fire: fix use-after-free on disconnect
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
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 6fire USB audio device driver. During the disconnection process of a 6fire USB audio device, a use-after-free vulnerability occurs. This happens when the system attempts to write to memory that has already been deallocated, which can lead to memory corruption and potentially cause system instability or a denial of service.
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Description OSIDB Bzimport 2026-04-24 15:03:22 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ALSA: 6fire: fix use-after-free on disconnect

In usb6fire_chip_abort(), the chip struct is allocated as the card's
private data (via snd_card_new with sizeof(struct sfire_chip)).  When
snd_card_free_when_closed() is called and no file handles are open, the
card and embedded chip are freed synchronously.  The subsequent
chip->card = NULL write then hits freed slab memory.

Call trace:
  usb6fire_chip_abort sound/usb/6fire/chip.c:59 [inline]
  usb6fire_chip_disconnect+0x348/0x358 sound/usb/6fire/chip.c:182
  usb_unbind_interface+0x1a8/0x88c drivers/usb/core/driver.c:458
  ...
  hub_event+0x1a04/0x4518 drivers/usb/core/hub.c:5953

Fix by moving the card lifecycle out of usb6fire_chip_abort() and into
usb6fire_chip_disconnect().  The card pointer is saved in a local
before any teardown, snd_card_disconnect() is called first to prevent
new opens, URBs are aborted while chip is still valid, and
snd_card_free_when_closed() is called last so chip is never accessed
after the card may be freed.
Comment 1 Keith Grant 2026-04-24 18:28:08 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042411-CVE-2026-31581-9bc2@gregkh/T