CVE-2026-31581ALSA: 6fire: fix use-after-free on disconnect

Official description

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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/e719232f4552e29de8027a83918ea94434be87af
• https://git.kernel.org/stable/c/e247a0e01d15ed420f77ec5e2335721bf430a5b3
• https://git.kernel.org/stable/c/ba88461f7653636c48321ca993006a74724c2f41
• https://git.kernel.org/stable/c/e88354b381e2006de63d6b052ed7005c9a47d00e
• https://git.kernel.org/stable/c/af75b486f7e883e3422ece23c8d727e6815144a0
• https://git.kernel.org/stable/c/d21e8a2af4869b5890b34e081d5aeadc93e9cd5c
• https://git.kernel.org/stable/c/3dc20d1981d6a67d8184498a5da272942dde1e65
• https://git.kernel.org/stable/c/51f6532790b74ffdd6970bc848358a2838c1c185
• https://git.kernel.org/stable/c/b9c826916fdce6419b94eb0cd8810fdac18c2386