---
id: "CVE-2026-98837"
kind: "vulnerability"
aliases: ["CVE-2026-98837"]
title: "Linux kernel: failed caiaq USB audio probe leaves freed-memory read"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["linux-kernel", "package", "self-hosted", "usb-audio"]
not_affected_if: ["module-not-loaded", "no-caiaq-hardware"]
published_at: "2026-10-18T16:17:37+00:00"
first_seen_at: "2026-10-23T21:57:17+00:00"
updated_at: "2026-10-25T05:13:14+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98837", "first_seen_at": "2026-10-23T21:57:17+00:00"}]
---

# Linux kernel: failed caiaq USB audio probe leaves freed-memory read

When the ALSA caiaq USB audio driver fails during probe, it frees device state but leaves its input device registered. Reading that device's uevent attribute afterwards reads freed kernel memory, which can crash the kernel or leak data.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- Install a Linux kernel build that includes the upstream fix that unregisters the input device on the probe error path in sound/usb/caiaq.
- unknown

## Timeline

- 2026-10-23T21:57:17+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98837

## From the sources

In the Linux kernel, the following vulnerability has been resolved:

ALSA: caiaq: unregister the input device when probe fails

setup_card() registers the input device, whose name and phys point into
struct snd_usb_caiaqdev, and then goes on to snd_card_register() and
snd_usb_caiaq_control_init(). If either fails, snd_probe() calls
snd_card_free(), which frees the device state but leaves the input
device registered: card_free() only clears the pointer, and the input
device is unregistered from snd_disconnect() alone. Reading its "uevent"
attribute afterwards dereferences freed memory:

  BUG: KASAN: slab-use-after-free in string+0x4a9/0x4f0
  Read of size 1 at addr ffff8880208f5043 by task caiaq/4967
   add_uevent_var+0x183/0x3a0
   input_dev_uevent+0x162/0x900
   dev_uevent+0x2f1/0x870
   uevent_show+0x1ca/0x3a0
   ...

Unregister the input device on the probe error path, as
snd_disconnect() does. snd_usb_caiaq_input_disconnect() is a no-op when
no input device was registered.

Reproduced with a raw-gadget Audio Kontrol 1 and a temporary hack that
makes snd_usb_caiaq_control_init() fail.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_