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comedi: Fix initialization of data for instructions that write to subdevice

Type: advisorySources: OSV

In the Linux kernel, the following vulnerability has been resolved: comedi: Fix initialization of data for instructions that write to subdevice Some Comedi subdevice instruction handlers are known to access instruction data elements beyond the first `insn->n` elements in some cases. The `do_insn_ioctl()` and `do_insnlist_ioctl()` functions allocate at least `MIN_SAMPLES` (16) data elements to deal with this, but they do not initialize all of that. For Comedi instruction codes that write to the subdevice, the first `insn->n` data elements are copied from user-space, but the remaining elements are left uninitialized. That could be a problem if the subdevice instruction handler reads the uninitialized data. Ensure that the first `MIN_SAMPLES` elements are initialized before calling these instruction handlers, filling the uncopied elements with 0. For `do_insnlist_ioctl()`, the same data buffer elements are used for handling a list of instructions, so ensure the first `MIN_SAMPLES` elements are initialized for each instruction that writes to the subdevice.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.241, 5.15.190, 5.4.297, 6.1.147, 6.12.40, 6.15.8, 6.6.100
CVEs
CVE-2025-38478
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 08:49 UTC · Revision 1

Source evidence

comedi: Fix initialization of data for instructions that write to subdevice

core-osv · Original source

Published 28 Jul 2025, 11:21 UTC

In the Linux kernel, the following vulnerability has been resolved: comedi: Fix initialization of data for instructions that write to subdevice Some Comedi subdevice instruction handlers are known to access instruction data elements beyond the first `insn->n` elements in some cases. The `do_insn_ioctl()` and `do_insnlist_ioctl()` functions allocate at least `MIN_SAMPLES` (16) data elements to deal with this, but they do not initialize all of that. For Comedi instruction codes that write to the subdevice, the first `insn->n` data elements are copied from user-space, but the remaining elements are left uninitialized. That could be a problem if the subdevice instruction handler reads the uninitialized data. Ensure that the first `MIN_SAMPLES` elements are initialized before calling these instruction handlers, filling the uncopied elements with 0. For `do_insnlist_ioctl()`, the same data buffer elements are used for handling a list of instructions, so ensure the first `MIN_SAMPLES` elements are initialized for each instruction that writes to the subdevice.

osv:CVE-2025-38478

Kernel

Fixed versions: 5.4.297, 5.10.241, 5.15.190, 6.1.147, 6.6.100, 6.12.40, 6.15.8

Complete source record
{
  "id": "1ae20e09698fb3f99944fbd967872daa85b2241f9a96e50da363086922831e93",
  "url": "https://osv.dev/vulnerability/CVE-2025-38478",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "comedi: Fix initialization of data for instructions that write to subdevice",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: comedi: Fix initialization of data for instructions that write to subdevice Some Comedi subdevice instruction handlers are known to access instruction data elements beyond the first `insn->n` elements in some cases. The `do_insn_ioctl()` and `do_insnlist_ioctl()` functions allocate at least `MIN_SAMPLES` (16) data elements to deal with this, but they do not initialize all of that. For Comedi instruction codes that write to the subdevice, the first `insn->n` data elements are copied from user-space, but the remaining elements are left uninitialized. That could be a problem if the subdevice instruction handler reads the uninitialized data. Ensure that the first `MIN_SAMPLES` elements are initialized before calling these instruction handlers, filling the uncopied elements with 0. For `do_insnlist_ioctl()`, the same data buffer elements are used for handling a list of instructions, so ensure the first `MIN_SAMPLES` elements are initialized for each instruction that writes to the subdevice.",
    "evidence": "osv:CVE-2025-38478",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.4.297",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.10.241",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.190",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.147",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.100",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.15.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-38478",
      "aliases": [
        "CVE-2025-38478"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "introduced": "ed9eccbe8970f6eedc1b978c157caf1251a896d4"
                },
                {
                  "fixed": "6f38c6380c3b38a05032b8881e41137385a6ce02"
                },
                {
                  "fixed": "13e4d9038a1e869445a996a3f604a84ef52fe8f4"
                },
                {
                  "fixed": "020eed5681d0f9bced73970368078a92d6cfaa9c"
                },
                {
                  "fixed": "d3436638738ace8f101af7bdee2eae1bc38e9b29"
                },
                {
                  "fixed": "673ee92bd2d31055bca98a1d96b653f5284289c4"
                },
                {
                  "fixed": "c42116dc70af6664526f7aa82cf937824ab42649"
                },
                {
                  "fixed": "fe8713fb4e4e82a4f91910d9a41bf0613e69a0b9"
                },
                {
                  "fixed": "46d8c744136ce2454aa4c35c138cc06817f92b8e"
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              ]
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-38478.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "2.6.29"
                },
                {
                  "fixed": "5.4.297"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.5.0"
                },
                {
                  "fixed": "5.10.241"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.190"
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              ]
            },
            {
              "type": "ECOSYSTEM",
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                  "introduced": "5.16.0"
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            },
            {
              "type": "ECOSYSTEM",
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                {
                  "introduced": "6.2.0"
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                {
                  "fixed": "6.6.100"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.40"
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              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.15.8"
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-38478.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:34.407317899Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/020eed5681d0f9bced73970368078a92d6cfaa9c",
        "https://git.kernel.org/stable/c/13e4d9038a1e869445a996a3f604a84ef52fe8f4",
        "https://git.kernel.org/stable/c/46d8c744136ce2454aa4c35c138cc06817f92b8e",
        "https://git.kernel.org/stable/c/673ee92bd2d31055bca98a1d96b653f5284289c4",
        "https://git.kernel.org/stable/c/6f38c6380c3b38a05032b8881e41137385a6ce02",
        "https://git.kernel.org/stable/c/c42116dc70af6664526f7aa82cf937824ab42649",
        "https://git.kernel.org/stable/c/d3436638738ace8f101af7bdee2eae1bc38e9b29",
        "https://git.kernel.org/stable/c/fe8713fb4e4e82a4f91910d9a41bf0613e69a0b9",
        "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html",
        "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38478.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-38478",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38478.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-38478",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 501258,
  "published_at": "2025-07-28T11:21:44.21+00:00"
}