CVE-2026-64134 (GCVE-0-2026-64134)
Vulnerability from cvelistv5
Published
2026-07-19 15:40
Modified
2026-08-05 12:39
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Don't setup bogus iov_iter for silencing At transition to the iov_iter for PCM data transfer, we blindly applied the iov_iter setup also for silencing (i.e. data = NULL), and it leads to a calculation of bogus iov_iter. Fortunately this didn't cause troubles on most of architectures but it goes wrong on RISC-V now, causing a NULL dereference. Handle the NULL data case to treat the silencing in interleaved_copy() for addressing the bug above. noninterleaved_copy() has already the NULL data handling, so it doesn't need changes.
References
Impacted products
Vendor Product Version
Linux Linux Version: cf393babb37a1679a1ec1d864df1090353465e23
Version: cf393babb37a1679a1ec1d864df1090353465e23
Version: cf393babb37a1679a1ec1d864df1090353465e23
Version: cf393babb37a1679a1ec1d864df1090353465e23
Version: cf393babb37a1679a1ec1d864df1090353465e23
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{
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          "programFiles": [
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              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
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          "nodes": [
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              "cpeMatch": [
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              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: pcm: Don\u0027t setup bogus iov_iter for silencing\n\nAt transition to the iov_iter for PCM data transfer, we blindly\napplied the iov_iter setup also for silencing (i.e. data = NULL), and\nit leads to a calculation of bogus iov_iter.  Fortunately this didn\u0027t\ncause troubles on most of architectures but it goes wrong on RISC-V\nnow, causing a NULL dereference.\n\nHandle the NULL data case to treat the silencing in interleaved_copy()\nfor addressing the bug above.  noninterleaved_copy() has already the\nNULL data handling, so it doesn\u0027t need changes."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable code is reached only via local ALSA PCM interfaces\u2014opening `/dev/snd/pcmC*D*p`, `write()`/`ioctl()` on that device, or OSS PCM emulation\u2014not via any network-facing kernel protocol.\nAC:L - An attacker with PCM device access can reliably trigger silencing by setting `silence_size \u003e 0` via `SNDRV_PCM_IOCTL_SW_PARAMS`, using OSS playback (which auto-enables silence), calling `snd_pcm_lib_write()` with a NULL buffer, or starting playback so `snd_pcm_playback_silence()` runs on interleaved streams.\nPR:L - Exploitation requires a local process able to open and configure a PCM playback stream (typically any logged-in desktop/mobile user with audio device access via the `audio` group, seat ACL, or equivalent permissions), not root or special capabilities.\nUI:N - Triggering the bug requires only programmatic PCM playback/silencing operations; no victim interaction such as mounting a filesystem or opening a malicious file is needed.\nS:U - Impact is confined to kernel memory safety within the ALSA PCM subsystem on the local host; it does not cross a security boundary such as VM escape, sandbox escape, or IOMMU bypass.\nC:H - Passing `data=NULL` through `do_transfer()` constructs a bogus `iov_iter` with a NULL base pointer; this is a kernel memory-safety defect in the iterator layer that can cause out-of-bounds or NULL-based reads when iterator helpers dereference the malformed state, not merely a benign error return.\nI:H - The same bogus `iov_iter` setup supplies invalid source/destination metadata to the kernel copy path; if iterator operations proceed on the malformed structure, uncontrolled kernel writes are possible, and the identical NULL-handling gap in `noninterleaved_copy()` confirms this silencing path was always meant to bypass `do_transfer()`.\nA:H - On RISC-V the defect manifests as a kernel NULL pointer dereference during silencing, causing an oops/panic and denial of service; the bug is also reachable on every architecture where interleaved PCM silencing is used."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:39:36.211Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/41a766c647294842c9b17672449f8e011048cba9"
        },
        {
          "url": "https://git.kernel.org/stable/c/ce836587e594af39ff048d9b29dee0f5f10692c9"
        },
        {
          "url": "https://git.kernel.org/stable/c/feff0251386aa6bb180a0a1cf7c1f91ba868113d"
        },
        {
          "url": "https://git.kernel.org/stable/c/c9f6768515818d71bdfc20119a81f3332c53b9c6"
        },
        {
          "url": "https://git.kernel.org/stable/c/e4d3386b74fba8e01280484b67ee481ece00201e"
        }
      ],
      "title": "ALSA: pcm: Don\u0027t setup bogus iov_iter for silencing",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64134",
    "datePublished": "2026-07-19T15:40:28.974Z",
    "dateReserved": "2026-07-19T07:54:57.036Z",
    "dateUpdated": "2026-08-05T12:39:36.211Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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