---
id: CVE-2026-89881
title: >-
  In the Linux kernel, the following vulnerability has been resolved:


  media: rtl2832_sdr: use vb2_video_unregister_device() on remove to fix DMA
  leak


  rtl2832_sdr_remove() runs on USB disconnect and clears dev->udev to

  NULL before any pen…
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  media: rtl2832_sdr: use vb2_video_unregister_device() on remove to fix DMA
  leak


  rtl2832_sdr_remove() runs on USB disconnect and clears dev->udev to

  NULL before any pen…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 771138920eafa399f68d3492c8a75dfeea23474b <
    234c46b95a032232e31fa5987b84fb8f87a9693b
  - >-
    Linux >= 771138920eafa399f68d3492c8a75dfeea23474b <
    034b6a4f9589c04bc3f2bd5125658cd72d3e17c8
  - >-
    Linux >= 771138920eafa399f68d3492c8a75dfeea23474b <
    0ef9f19010ae4ba93aca211ea8f0081b9bf7aab2
  - >-
    Linux >= 771138920eafa399f68d3492c8a75dfeea23474b <
    053581d4657c6b5289c5de71a4828d313c005189
  - >-
    Linux >= 771138920eafa399f68d3492c8a75dfeea23474b <
    bbf15e83c37d9ac938b7c35c02b748fe54230010
  - >-
    Linux >= 771138920eafa399f68d3492c8a75dfeea23474b <
    7443b16b6dd8889a3b9c5236a09e7c58f0d11dae
  - >-
    Linux >= 771138920eafa399f68d3492c8a75dfeea23474b <
    a0d9d9a3b41a1346c26af57aade6ba3f552fa171
  - >-
    Linux >= 771138920eafa399f68d3492c8a75dfeea23474b <
    dabb047c62668f280998e29117c55e41aabac336
  - Linux 3.15
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T11:16:56.503'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89881'
references:
  - url: 'https://git.kernel.org/stable/c/034b6a4f9589c04bc3f2bd5125658cd72d3e17c8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/053581d4657c6b5289c5de71a4828d313c005189'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/0ef9f19010ae4ba93aca211ea8f0081b9bf7aab2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/234c46b95a032232e31fa5987b84fb8f87a9693b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7443b16b6dd8889a3b9c5236a09e7c58f0d11dae'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a0d9d9a3b41a1346c26af57aade6ba3f552fa171'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bbf15e83c37d9ac938b7c35c02b748fe54230010'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dabb047c62668f280998e29117c55e41aabac336'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-16T10:53:53.984Z'
epss: 0.0021
epssPercentile: 0.10067
---

## Overview

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

media: rtl2832_sdr: use vb2_video_unregister_device() on remove to fix DMA leak

rtl2832_sdr_remove() runs on USB disconnect and clears dev->udev to
NULL before any pending streaming teardown has run. When user space
later closes its file descriptor, vb2 calls rtl2832_sdr_stop_streaming()
which in turn calls rtl2832_sdr_free_stream_bufs(). That helper releases
each coherent buffer with:

    usb_free_coherent(dev->udev, dev->buf_size,
                      dev->buf_list[dev->buf_num],
                      dev->dma_addr[dev->buf_num]);

usb_free_coherent() returns immediately when its dev argument is NULL,
so every DMA stream buffer that was live at disconnect is silently
leaked. The URBs allocated in rtl2832_sdr_alloc_urbs() outlive the
device for the same reason.

The rtl2832_sdr driver uses vb2_fop_release() in its file_operations,
so replace video_unregister_device(&dev->vdev) with
vb2_video_unregister_device(&dev->vdev) and move it before clearing
dev->udev. vb2_video_unregister_device() releases the vb2 queue, which
synchronously runs rtl2832_sdr_stop_streaming() if streaming is active,
so URBs and coherent DMA stream buffers are freed while dev->udev is
still valid.

vb2_video_unregister_device() locks vdev->queue->lock (vb_queue_lock)
internally, and stop_streaming() locks v4l2_lock, so the previous outer
mutex_lock(&dev->vb_queue_lock) / mutex_lock(&dev->v4l2_lock) pair
around the unregister sequence would self-deadlock and has been removed.
A short v4l2_lock critical section around dev->udev = NULL remains so
any ioctl path that still holds the file descriptor sees coherent state.

Issue identified by automated review of the INV-003 series at
https://sashiko.dev/

## Remediation

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