---
id: CVE-2026-68363
title: >-
  wifi: ath9k: hif_usb: don't dereference hif_dev after re-arming firmware
  request
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  wifi: ath9k: hif_usb: don't dereference hif_dev after re-arming firmware
  request


  ath9k_hif_request_firmware() re-arms an asynchronous firmware load via

  request_firmwar…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc <
    47ed81aaa7f94d9808f4719e78a760c2ec1e6c86
  - >-
    Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc <
    48de0c6952192b0771fca468df4364d11ec74ad9
  - >-
    Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc <
    063497cc9f320ab71a7a937c3bc0a23e630aefe2
  - >-
    Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc <
    7f184ca38a90889f3f6665ff96748b95da39dbee
  - >-
    Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc <
    10b0ce629123a3737b4eda50188f73bb7be7b68b
  - >-
    Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc <
    48a69cedde7388294e4ea6fd804156cd62bc04fc
  - >-
    Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc <
    7c9046d92c4b9789c9d9d775e4fd5f34be64cb0a
  - >-
    Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc <
    dad9f96945d77ecd4708f730c06ef54dcd8cc057
  - Linux 4.4
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:48:07.946520Z'
published: '2026-08-10'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:55:14.386Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-68363'
references:
  - url: 'https://git.kernel.org/stable/c/47ed81aaa7f94d9808f4719e78a760c2ec1e6c86'
  - url: 'https://git.kernel.org/stable/c/48de0c6952192b0771fca468df4364d11ec74ad9'
  - url: 'https://git.kernel.org/stable/c/063497cc9f320ab71a7a937c3bc0a23e630aefe2'
  - url: 'https://git.kernel.org/stable/c/7f184ca38a90889f3f6665ff96748b95da39dbee'
  - url: 'https://git.kernel.org/stable/c/10b0ce629123a3737b4eda50188f73bb7be7b68b'
  - url: 'https://git.kernel.org/stable/c/48a69cedde7388294e4ea6fd804156cd62bc04fc'
  - url: 'https://git.kernel.org/stable/c/7c9046d92c4b9789c9d9d775e4fd5f34be64cb0a'
  - url: 'https://git.kernel.org/stable/c/dad9f96945d77ecd4708f730c06ef54dcd8cc057'
tags:
  - cve.org
epss: 0.00184
epssPercentile: 0.08082
ingestedAt: '2026-11-06T18:00:12.607Z'
---

## Overview

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

wifi: ath9k: hif_usb: don't dereference hif_dev after re-arming firmware request

ath9k_hif_request_firmware() re-arms an asynchronous firmware load via
request_firmware_nowait(), passing hif_dev as the completion context, and
then still dereferences hif_dev:

	dev_info(&hif_dev->udev->dev, "ath9k_htc: Firmware %s requested\n",
		 hif_dev->fw_name);

The re-armed callback ath9k_hif_usb_firmware_cb() runs on the "events"
workqueue and, when the firmware is missing, walks the retry chain into
ath9k_hif_usb_firmware_fail() -> complete_all(&hif_dev->fw_done). That
releases the wait_for_completion(&hif_dev->fw_done) in a concurrent
ath9k_hif_usb_disconnect(), which then kfree()s hif_dev. The trailing
dev_info() in the frame that re-armed the request can therefore read freed
memory (hif_dev->udev, the first field of struct hif_device_usb):

  BUG: KASAN: slab-use-after-free in ath9k_hif_request_firmware
  Read of size 8 ... by task kworker/...
   ath9k_hif_request_firmware
   ath9k_hif_usb_firmware_cb           drivers/net/wireless/ath/ath9k/hif_usb.c:1247
   request_firmware_work_func
  Allocated by ...:
   ath9k_hif_usb_probe                 drivers/net/wireless/ath/ath9k/hif_usb.c
  Freed by ...:
   ath9k_hif_usb_disconnect -> kfree   drivers/net/wireless/ath/ath9k/hif_usb.c

The fw_done barrier only makes disconnect wait for the firmware chain to
*terminate*; it does not protect the outer ath9k_hif_request_firmware()
frame that re-armed the request and keeps touching hif_dev afterwards.

Drop the post-request dev_info(): it is the only use of hif_dev after the
async request is armed, and it is purely informational (the dev_err() on the
failure path runs only when request_firmware_nowait() did not arm a callback,
so hif_dev is still alive there).

This was first reported by syzbot as a single, non-reproduced crash that was
later auto-obsoleted, and was independently rediscovered by the reFuzz fuzzer,
which produced a C reproducer (USB-gadget connect/disconnect of an ath9k_htc
device whose firmware download fails). The vulnerable code is unchanged and
still present in v7.1-rc6, where the slab-use-after-free reproduces under KASAN
once the (sub-microsecond) race window is widened.

## Affected

- `Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc < 47ed81aaa7f94d9808f4719e78a760c2ec1e6c86`
- `Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc < 48de0c6952192b0771fca468df4364d11ec74ad9`
- `Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc < 063497cc9f320ab71a7a937c3bc0a23e630aefe2`
- `Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc < 7f184ca38a90889f3f6665ff96748b95da39dbee`
- `Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc < 10b0ce629123a3737b4eda50188f73bb7be7b68b`
- `Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc < 48a69cedde7388294e4ea6fd804156cd62bc04fc`
- `Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc < 7c9046d92c4b9789c9d9d775e4fd5f34be64cb0a`
- `Linux >= e904cf6fe23022cde4e0ea9d41601411a315a3dc < dad9f96945d77ecd4708f730c06ef54dcd8cc057`
- `Linux 4.4`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.