CVE-2026-99271 (GCVE-0-2026-99271)

Vulnerability from cvelistv5 – Published: 2026-11-07 14:08 – Updated: 2026-11-10 18:15
VLAI
Title
ALSA: line6: Clear prev_fbuf on capture buffer release
Summary
In the Linux kernel, the following vulnerability has been resolved: ALSA: line6: Clear prev_fbuf on capture buffer release A KASAN slab-use-after-free read was reported in submit_audio_out_urb() when generating an impulse test signal: BUG: KASAN: slab-use-after-free in create_impulse_test_signal sound/usb/line6/playback.c:76 [inline] BUG: KASAN: slab-use-after-free in submit_audio_out_urb+0x1848/0x1b20 sound/usb/line6/playback.c:249 Read of size 2 at addr ffff888008d74870 by task syz.2.3214/7785 Allocated by task 11: kmem_cache_alloc_noprof+0x2f0/0x390 mm/slub.c:4144 line6_buffer_acquire+0x1a1/0x220 sound/usb/line6/pcm.c:158 line6_pcm_acquire+0xb6/0x230 sound/usb/line6/pcm.c:329 line6_startup_work+0x3c/0x50 sound/usb/line6/driver.c:728 Freed by task 7785: kfree+0xf8/0x390 mm/slub.c:6566 line6_buffer_release sound/usb/line6/pcm.c:176 [inline] line6_buffer_release+0xa5/0xf0 sound/usb/line6/pcm.c:170 __line6_pcm_release sound/usb/line6/pcm.c:305 [inline] line6_pcm_release+0x5a/0x80 sound/usb/line6/pcm.c:313 snd_toneport_monitor_put+0x11b/0x190 sound/usb/line6/toneport.c:183 line6pcm->prev_fbuf points into the capture PCM stream buffer (line6pcm->in.buffer), which is updated during audio_in_callback() to feed rate synchronization, software monitoring, and impulse test signal generation on playback side. When all capture streams are closed, line6_buffer_release() frees pstr->buffer with kfree(). However, it does not clear line6pcm->prev_fbuf. If playback is subsequently started (e.g. via impulse test signal volume control snd_line6_impulse_volume_put()), submit_audio_out_urb() dereferences the stale pointer line6pcm->prev_fbuf under in.lock, resulting in a slab-use-after-free read. Clear prev_fbuf and prev_fsize in line6_buffer_release() when releasing the capture stream buffer under in.lock, ensuring that no stale buffer pointer can be accessed by submit_audio_out_urb().
Severity
No CVSS data available.
Assigner
Linux CNA
References
Impacted products
Vendor Product Version
Linux Linux Affected: 63e20df1e5b2ef8d871ecbdb6c038d554ed1ca74 , < d063975ed22cdc2cb609a9828e5f658448193606 (git)
Affected: 63e20df1e5b2ef8d871ecbdb6c038d554ed1ca74 , < 862d9268f40a6e10cef24eb226e738fb69ce8aa7 (git)
Affected: 63e20df1e5b2ef8d871ecbdb6c038d554ed1ca74 , < 22c82f33ff0b68d37041adf1dea5533a5863cd31 (git)
Affected: 63e20df1e5b2ef8d871ecbdb6c038d554ed1ca74 , < aa118c8f61d59387961d58ffae831c5259a9f222 (git)
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Linux Linux Affected: 4.0
Unaffected: 0 , < 4.0 (semver)
Unaffected: 6.12.117 , ≤ 6.12.* (semver)
Unaffected: 6.18.61 , ≤ 6.18.* (semver)
Unaffected: 7.3.2 , ≤ 7.3.* (semver)
Unaffected: 7.4-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "sound/usb/line6/pcm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "d063975ed22cdc2cb609a9828e5f658448193606",
              "status": "affected",
              "version": "63e20df1e5b2ef8d871ecbdb6c038d554ed1ca74",
              "versionType": "git"
            },
            {
              "lessThan": "862d9268f40a6e10cef24eb226e738fb69ce8aa7",
              "status": "affected",
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              "versionType": "git"
            },
            {
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              "version": "63e20df1e5b2ef8d871ecbdb6c038d554ed1ca74",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "sound/usb/line6/pcm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.0"
            },
            {
              "lessThan": "4.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.117",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.61",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.3.*",
              "status": "unaffected",
              "version": "7.3.2",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.4-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.117",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.61",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3.2",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.4-rc1",
                  "versionStartIncluding": "4.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: line6: Clear prev_fbuf on capture buffer release\n\nA KASAN slab-use-after-free read was reported in submit_audio_out_urb()\nwhen generating an impulse test signal:\n\n  BUG: KASAN: slab-use-after-free in create_impulse_test_signal sound/usb/line6/playback.c:76 [inline]\n  BUG: KASAN: slab-use-after-free in submit_audio_out_urb+0x1848/0x1b20 sound/usb/line6/playback.c:249\n  Read of size 2 at addr ffff888008d74870 by task syz.2.3214/7785\n\n  Allocated by task 11:\n   kmem_cache_alloc_noprof+0x2f0/0x390 mm/slub.c:4144\n   line6_buffer_acquire+0x1a1/0x220 sound/usb/line6/pcm.c:158\n   line6_pcm_acquire+0xb6/0x230 sound/usb/line6/pcm.c:329\n   line6_startup_work+0x3c/0x50 sound/usb/line6/driver.c:728\n\n  Freed by task 7785:\n   kfree+0xf8/0x390 mm/slub.c:6566\n   line6_buffer_release sound/usb/line6/pcm.c:176 [inline]\n   line6_buffer_release+0xa5/0xf0 sound/usb/line6/pcm.c:170\n   __line6_pcm_release sound/usb/line6/pcm.c:305 [inline]\n   line6_pcm_release+0x5a/0x80 sound/usb/line6/pcm.c:313\n   snd_toneport_monitor_put+0x11b/0x190 sound/usb/line6/toneport.c:183\n\nline6pcm-\u003eprev_fbuf points into the capture PCM stream buffer\n(line6pcm-\u003ein.buffer), which is updated during audio_in_callback() to\nfeed rate synchronization, software monitoring, and impulse test signal\ngeneration on playback side.\n\nWhen all capture streams are closed, line6_buffer_release() frees\npstr-\u003ebuffer with kfree().  However, it does not clear line6pcm-\u003eprev_fbuf.\nIf playback is subsequently started (e.g. via impulse test signal\nvolume control snd_line6_impulse_volume_put()), submit_audio_out_urb()\ndereferences the stale pointer line6pcm-\u003eprev_fbuf under in.lock,\nresulting in a slab-use-after-free read.\n\nClear prev_fbuf and prev_fsize in line6_buffer_release() when releasing\nthe capture stream buffer under in.lock, ensuring that no stale buffer\npointer can be accessed by submit_audio_out_urb()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-10T18:15:27.042Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d063975ed22cdc2cb609a9828e5f658448193606"
        },
        {
          "url": "https://git.kernel.org/stable/c/862d9268f40a6e10cef24eb226e738fb69ce8aa7"
        },
        {
          "url": "https://git.kernel.org/stable/c/22c82f33ff0b68d37041adf1dea5533a5863cd31"
        },
        {
          "url": "https://git.kernel.org/stable/c/aa118c8f61d59387961d58ffae831c5259a9f222"
        }
      ],
      "title": "ALSA: line6: Clear prev_fbuf on capture buffer release",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-99271",
    "datePublished": "2026-11-07T14:08:45.047Z",
    "dateReserved": "2026-09-25T10:25:14.404Z",
    "dateUpdated": "2026-11-10T18:15:27.042Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}



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