rootpwn

high · CVSS v3 7.8

CVE-2026-98006

CVE-2026-98006 is a use-after-free vulnerability in the Linux kernel's ALSA caiaq driver. The vulnerability occurs due to improper managemen

Overview

CVE-2026-98006 is a use-after-free vulnerability in the Linux kernel's ALSA caiaq driver. The vulnerability occurs due to improper management of USB URB objects during card freeing, specifically with `ep1_in_urb` and `midi_out_urb`. This can lead to kernel crashes and potential instability.

Description

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

Impact

Successful exploitation could lead to a kernel panic (system crash) and denial of service. Confidentiality and integrity are not directly impacted, but system availability is compromised. This affects systems utilizing the affected ALSA caiaq driver.

Remediation

Apply the patch provided by your Linux distribution vendor. Ensure kernel updates are regularly applied to address security vulnerabilities. Review kernel logs for any related error messages or crashes.

Risk context

This vulnerability has a CVSS v3 score of 7.8 (High severity). While an EPSS score is not available, the potential for a kernel panic warrants prompt attention. Prioritize patching based on system criticality and exposure.

Affected products

  • Linux Kernel
  • ALSA caiaq driver

Scores

Severity
high
CVSS v2
7.2
CVSS v3
7.8
CVSS v4
—
EPSS
—

linux kernel alsa caiaq use-after-free usb kernel crash security patch

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