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FKIE_CVE-2026-89881

Vulnerability from fkie_nvd - Published: 2026-09-16 11:16 - Updated: 2026-09-16 11:16
Severity
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 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/
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/034b6a4f9589c04bc3f2bd5125658cd72d3e17c8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/053581d4657c6b5289c5de71a4828d313c005189
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0ef9f19010ae4ba93aca211ea8f0081b9bf7aab2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/234c46b95a032232e31fa5987b84fb8f87a9693b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7443b16b6dd8889a3b9c5236a09e7c58f0d11dae
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a0d9d9a3b41a1346c26af57aade6ba3f552fa171
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bbf15e83c37d9ac938b7c35c02b748fe54230010
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dabb047c62668f280998e29117c55e41aabac336
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/media/dvb-frontends/rtl2832_sdr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "234c46b95a032232e31fa5987b84fb8f87a9693b",
              "status": "affected",
              "version": "771138920eafa399f68d3492c8a75dfeea23474b",
              "versionType": "git"
            },
            {
              "lessThan": "034b6a4f9589c04bc3f2bd5125658cd72d3e17c8",
              "status": "affected",
              "version": "771138920eafa399f68d3492c8a75dfeea23474b",
              "versionType": "git"
            },
            {
              "lessThan": "0ef9f19010ae4ba93aca211ea8f0081b9bf7aab2",
              "status": "affected",
              "version": "771138920eafa399f68d3492c8a75dfeea23474b",
              "versionType": "git"
            },
            {
              "lessThan": "053581d4657c6b5289c5de71a4828d313c005189",
              "status": "affected",
              "version": "771138920eafa399f68d3492c8a75dfeea23474b",
              "versionType": "git"
            },
            {
              "lessThan": "bbf15e83c37d9ac938b7c35c02b748fe54230010",
              "status": "affected",
              "version": "771138920eafa399f68d3492c8a75dfeea23474b",
              "versionType": "git"
            },
            {
              "lessThan": "7443b16b6dd8889a3b9c5236a09e7c58f0d11dae",
              "status": "affected",
              "version": "771138920eafa399f68d3492c8a75dfeea23474b",
              "versionType": "git"
            },
            {
              "lessThan": "a0d9d9a3b41a1346c26af57aade6ba3f552fa171",
              "status": "affected",
              "version": "771138920eafa399f68d3492c8a75dfeea23474b",
              "versionType": "git"
            },
            {
              "lessThan": "dabb047c62668f280998e29117c55e41aabac336",
              "status": "affected",
              "version": "771138920eafa399f68d3492c8a75dfeea23474b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/media/dvb-frontends/rtl2832_sdr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.15"
            },
            {
              "lessThan": "3.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: rtl2832_sdr: use vb2_video_unregister_device() on remove to fix DMA leak\n\nrtl2832_sdr_remove() runs on USB disconnect and clears dev-\u003eudev to\nNULL before any pending streaming teardown has run. When user space\nlater closes its file descriptor, vb2 calls rtl2832_sdr_stop_streaming()\nwhich in turn calls rtl2832_sdr_free_stream_bufs(). That helper releases\neach coherent buffer with:\n\n    usb_free_coherent(dev-\u003eudev, dev-\u003ebuf_size,\n                      dev-\u003ebuf_list[dev-\u003ebuf_num],\n                      dev-\u003edma_addr[dev-\u003ebuf_num]);\n\nusb_free_coherent() returns immediately when its dev argument is NULL,\nso every DMA stream buffer that was live at disconnect is silently\nleaked. The URBs allocated in rtl2832_sdr_alloc_urbs() outlive the\ndevice for the same reason.\n\nThe rtl2832_sdr driver uses vb2_fop_release() in its file_operations,\nso replace video_unregister_device(\u0026dev-\u003evdev) with\nvb2_video_unregister_device(\u0026dev-\u003evdev) and move it before clearing\ndev-\u003eudev. vb2_video_unregister_device() releases the vb2 queue, which\nsynchronously runs rtl2832_sdr_stop_streaming() if streaming is active,\nso URBs and coherent DMA stream buffers are freed while dev-\u003eudev is\nstill valid.\n\nvb2_video_unregister_device() locks vdev-\u003equeue-\u003elock (vb_queue_lock)\ninternally, and stop_streaming() locks v4l2_lock, so the previous outer\nmutex_lock(\u0026dev-\u003evb_queue_lock) / mutex_lock(\u0026dev-\u003ev4l2_lock) pair\naround the unregister sequence would self-deadlock and has been removed.\nA short v4l2_lock critical section around dev-\u003eudev = NULL remains so\nany ioctl path that still holds the file descriptor sees coherent state.\n\nIssue identified by automated review of the INV-003 series at\nhttps://sashiko.dev/"
    }
  ],
  "id": "CVE-2026-89881",
  "lastModified": "2026-09-16T11:16:56.503",
  "metrics": {},
  "published": "2026-09-16T11:16:56.503",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/034b6a4f9589c04bc3f2bd5125658cd72d3e17c8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/053581d4657c6b5289c5de71a4828d313c005189"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0ef9f19010ae4ba93aca211ea8f0081b9bf7aab2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/234c46b95a032232e31fa5987b84fb8f87a9693b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7443b16b6dd8889a3b9c5236a09e7c58f0d11dae"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a0d9d9a3b41a1346c26af57aade6ba3f552fa171"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bbf15e83c37d9ac938b7c35c02b748fe54230010"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dabb047c62668f280998e29117c55e41aabac336"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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