---
id: CVE-2026-63821
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  wifi: rtw88: usb: fix memory leaks on USB write failures

  When rtw_usb_write_port() fails to submit a USB Request Block (URB)
  (e.g., due to device disconnect or ENOMEM)…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  wifi: rtw88: usb: fix memory leaks on USB write failures

  When rtw_usb_write_port() fails to submit a USB Request Block (URB)
  (e.g., due to device disconnect or ENOMEM)…
severity: none
published: '2026-07-19'
updated: '2026-08-17'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63821'
references:
  - url: 'https://git.kernel.org/stable/c/200d58c851b8f63f77a05570072dd20f79bc3681'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2b2060c2075a72bc2de43ce5e1b9347d6c5e27bb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/53fed4061a09755de99c89fdc7fae5b794da455f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6b964941bbfe6e0f18b1a5e008486dbb62df440a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8206d173d18ef5a077423119f4e9a93cb3a6f4eb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00166
epssPercentile: 0.05176
ingestedAt: '2026-08-17T05:47:49.772Z'
---

## Overview

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

wifi: rtw88: usb: fix memory leaks on USB write failures

When rtw_usb_write_port() fails to submit a USB Request Block (URB)
(e.g., due to device disconnect or ENOMEM), the completion callback is
never executed.

Currently, the driver ignores the return value of rtw_usb_write_port()
in rtw_usb_write_data() and rtw_usb_tx_agg_skb(). Because these
functions rely on the completion callback to free the socket buffers
(skbs) and the transaction control block (txcb), a submission failure
results in:
1. A memory leak of the allocated skb in rtw_usb_write_data().
2. A memory leak of the txcb structure and all aggregated skbs in
   rtw_usb_tx_agg_skb().

Fix this by checking the return value of rtw_usb_write_port(). If it
fails, explicitly free the skb in rtw_usb_write_data(), and properly
purge the tx_ack_queue and free the txcb in rtw_usb_tx_agg_skb().

The issue was discovered in practice during device disconnect/reconnect
scenarios and memory pressure conditions. Tested by verifying normal TX
operation continues after the fix without regressions.

## Remediation

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