---
id: CVE-2023-53641
title: 'wifi: ath9k: hif_usb: fix memory leak of remain_skbs'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  wifi: ath9k: hif_usb: fix memory leak of remain_skbs

  hif_dev->remain_skb is allocated and used exclusively in
  ath9k_hif_usb_rx_stream(). It is implied that an allocate…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= fb9987d0f748c983bb795a86f47522313f701a08 <
    6719e3797ec52cd144c8a5ba8aaab36674800585
  - >-
    Linux >= fb9987d0f748c983bb795a86f47522313f701a08 <
    d9899318660791141ea6002fda5577b2c5d7386e
  - >-
    Linux >= fb9987d0f748c983bb795a86f47522313f701a08 <
    320d760a35273aa815d58b57e4fd9ba5279a3489
  - >-
    Linux >= fb9987d0f748c983bb795a86f47522313f701a08 <
    59073060fe0950c6ecbe12bdc06469dcac62128d
  - >-
    Linux >= fb9987d0f748c983bb795a86f47522313f701a08 <
    9b9356a3014123f0ce4b50d9278c1265173150ab
  - >-
    Linux >= fb9987d0f748c983bb795a86f47522313f701a08 <
    f0931fc8f4b6847c72e170d2326861c0a081d680
  - >-
    Linux >= fb9987d0f748c983bb795a86f47522313f701a08 <
    8f02d538878c9b1501f624595eb22ee4e5e0ff84
  - >-
    Linux >= fb9987d0f748c983bb795a86f47522313f701a08 <
    7654cc03eb699297130b693ec34e25f77b17c947
  - Linux 2.6.35
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T20:26:20.455760Z'
published: '2025-10-07'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T20:31:19.142Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2023-53641'
references:
  - url: 'https://git.kernel.org/stable/c/6719e3797ec52cd144c8a5ba8aaab36674800585'
  - url: 'https://git.kernel.org/stable/c/d9899318660791141ea6002fda5577b2c5d7386e'
  - url: 'https://git.kernel.org/stable/c/320d760a35273aa815d58b57e4fd9ba5279a3489'
  - url: 'https://git.kernel.org/stable/c/59073060fe0950c6ecbe12bdc06469dcac62128d'
  - url: 'https://git.kernel.org/stable/c/9b9356a3014123f0ce4b50d9278c1265173150ab'
  - url: 'https://git.kernel.org/stable/c/f0931fc8f4b6847c72e170d2326861c0a081d680'
  - url: 'https://git.kernel.org/stable/c/8f02d538878c9b1501f624595eb22ee4e5e0ff84'
  - url: 'https://git.kernel.org/stable/c/7654cc03eb699297130b693ec34e25f77b17c947'
tags:
  - cve.org
epss: 0.0016
epssPercentile: 0.05158
ingestedAt: '2026-11-05T22:38:31.821Z'
---

## Overview

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

wifi: ath9k: hif_usb: fix memory leak of remain_skbs

hif_dev->remain_skb is allocated and used exclusively in
ath9k_hif_usb_rx_stream(). It is implied that an allocated remain_skb is
processed and subsequently freed (in error paths) only during the next
call of ath9k_hif_usb_rx_stream().

So, if the urbs are deallocated between those two calls due to the device
deinitialization or suspend, it is possible that ath9k_hif_usb_rx_stream()
is not called next time and the allocated remain_skb is leaked. Our local
Syzkaller instance was able to trigger that.

remain_skb makes sense when receiving two consecutive urbs which are
logically linked together, i.e. a specific data field from the first skb
indicates a cached skb to be allocated, memcpy'd with some data and
subsequently processed in the next call to ath9k_hif_usb_rx_stream(). Urbs
deallocation supposedly makes that link irrelevant so we need to free the
cached skb in those cases.

Fix the leak by introducing a function to explicitly free remain_skb (if
it is not NULL) when the rx urbs have been deallocated. remain_skb is NULL
when it has not been allocated at all (hif_dev struct is kzalloced) or
when it has been processed in next call to ath9k_hif_usb_rx_stream().

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

## Affected

- `Linux >= fb9987d0f748c983bb795a86f47522313f701a08 < 6719e3797ec52cd144c8a5ba8aaab36674800585`
- `Linux >= fb9987d0f748c983bb795a86f47522313f701a08 < d9899318660791141ea6002fda5577b2c5d7386e`
- `Linux >= fb9987d0f748c983bb795a86f47522313f701a08 < 320d760a35273aa815d58b57e4fd9ba5279a3489`
- `Linux >= fb9987d0f748c983bb795a86f47522313f701a08 < 59073060fe0950c6ecbe12bdc06469dcac62128d`
- `Linux >= fb9987d0f748c983bb795a86f47522313f701a08 < 9b9356a3014123f0ce4b50d9278c1265173150ab`
- `Linux >= fb9987d0f748c983bb795a86f47522313f701a08 < f0931fc8f4b6847c72e170d2326861c0a081d680`
- `Linux >= fb9987d0f748c983bb795a86f47522313f701a08 < 8f02d538878c9b1501f624595eb22ee4e5e0ff84`
- `Linux >= fb9987d0f748c983bb795a86f47522313f701a08 < 7654cc03eb699297130b693ec34e25f77b17c947`
- `Linux 2.6.35`

## Remediation

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