Bug 2461471 (CVE-2026-31581) - CVE-2026-31581 kernel: ALSA: 6fire: fix use-after-free on disconnect
Summary: CVE-2026-31581 kernel: ALSA: 6fire: fix use-after-free on disconnect
Keywords:
Status: NEW
Alias: CVE-2026-31581
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-24 15:03 UTC by OSIDB Bzimport
Modified: 2026-04-24 18:30 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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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.


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