Bug 2541304 (CVE-2026-98006) - CVE-2026-98006 kernel: ALSA: caiaq: Decoupling ep1_in_urb in caiaq dev
Summary: CVE-2026-98006 kernel: ALSA: caiaq: Decoupling ep1_in_urb in caiaq dev
Keywords:
Status: NEW
Alias: CVE-2026-98006
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-25 11:17 UTC by OSIDB Bzimport
Modified: 2026-09-28 19:05 UTC (History)
17 users (show)

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


Attachments (Terms of Use)

Description OSIDB Bzimport 2026-09-25 11:17:19 UTC
In the Linux kernel, the following vulnerability has been resolved:

ALSA: caiaq: Decoupling ep1_in_urb in caiaq dev

The epq_in_urb object belonging to the caiaq device is coupled within
the struct snd_usb_caiaqdev. After usb_submit_urb(epq_in_urb, GFP_KERNEL)
executes successfully, epq_in_urb is successfully added to the urbp_list
queue of the dummy HCD driver (userspace specifies dummy_hcd as the HCD
layer driver for the caiaq USB device).

When init_card() calls snd_usb_caiaq_send_command() which subsequently
fails due to a timeout, and proceeds to call snd_card_free() to release
the card, the embedded ep1_in_urb object is also freed. When the dummy
HCD driver detects that the URB has been unlinked, it returns the URB
(by usb_hcd_giveback_urb()), which triggers [1].

Decouple the ep1_in_urb object from the struct snd_usb_caiaqdev and switch
to using a pointer instead. Separately allocate and manage the memory for
ep1_in_urb to prevent the release of the snd_card memory object from
interfering with it.

midi_out_urb has the same issue as ep1_in_urb and is handled in the same
way.

[1]
BUG: KASAN: slab-use-after-free in usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
Write of size 4 at addr ffff88803cee1050 by task ktimers/1/29
Call Trace:
 usb_free_urb+0x24/0x120 drivers/usb/core/urb.c:96
 dummy_timer+0xaac/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:2019
 __run_hrtimer kernel/time/hrtimer.c:2067 [inline]
 __hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2124
 hrtimer_run_softirq+0x1e1/0x2e0 kernel/time/hrtimer.c:2141

Allocated by task 36:
 snd_card_new+0x7b/0x110 sound/core/init.c:184
 create_card sound/usb/caiaq/device.c:429 [inline]
 snd_probe+0x236/0x1af0 sound/usb/caiaq/device.c:544

Freed by task 36:
 snd_card_free_when_closed sound/core/init.c:630 [inline]
 snd_card_free+0x138/0x1d0 sound/core/init.c:662
 snd_probe+0x162b/0x1af0 sound/usb/caiaq/device.c:553


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