GHSA-55HQ-RJFV-397F

Vulnerability from github – Published: 2025-07-28 12:30 – Updated: 2025-12-23 18:30
VLAI?
Details

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.

Severity ?
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2025-38478"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-908"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-07-28T12:15:29Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncomedi: Fix initialization of data for instructions that write to subdevice\n\nSome Comedi subdevice instruction handlers are known to access\ninstruction data elements beyond the first `insn-\u003en` elements in some\ncases.  The `do_insn_ioctl()` and `do_insnlist_ioctl()` functions\nallocate at least `MIN_SAMPLES` (16) data elements to deal with this,\nbut they do not initialize all of that.  For Comedi instruction codes\nthat write to the subdevice, the first `insn-\u003en` data elements are\ncopied from user-space, but the remaining elements are left\nuninitialized.  That could be a problem if the subdevice instruction\nhandler reads the uninitialized data.  Ensure that the first\n`MIN_SAMPLES` elements are initialized before calling these instruction\nhandlers, filling the uncopied elements with 0.  For\n`do_insnlist_ioctl()`, the same data buffer elements are used for\nhandling a list of instructions, so ensure the first `MIN_SAMPLES`\nelements are initialized for each instruction that writes to the\nsubdevice.",
  "id": "GHSA-55hq-rjfv-397f",
  "modified": "2025-12-23T18:30:20Z",
  "published": "2025-07-28T12:30:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38478"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/020eed5681d0f9bced73970368078a92d6cfaa9c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/13e4d9038a1e869445a996a3f604a84ef52fe8f4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/46d8c744136ce2454aa4c35c138cc06817f92b8e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/673ee92bd2d31055bca98a1d96b653f5284289c4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6f38c6380c3b38a05032b8881e41137385a6ce02"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c42116dc70af6664526f7aa82cf937824ab42649"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d3436638738ace8f101af7bdee2eae1bc38e9b29"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fe8713fb4e4e82a4f91910d9a41bf0613e69a0b9"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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