{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-39686",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2025-39686"
  ],
  "published": "2025-09-05T17:22:05Z",
  "summary": "comedi: Make insn_rw_emulate_bits() do insn->n samples",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncomedi: Make insn_rw_emulate_bits() do insn->n samples\n\nThe `insn_rw_emulate_bits()` function is used as a default handler for\n`INSN_READ` instructions for subdevices that have a handler for\n`INSN_BITS` but not for `INSN_READ`.  Similarly, it is used as a default\nhandler for `INSN_WRITE` instructions for subdevices that have a handler\nfor `INSN_BITS` but not for `INSN_WRITE`. It works by emulating the\n`INSN_READ` or `INSN_WRITE` instruction handling with a constructed\n`INSN_BITS` instruction.  However, `INSN_READ` and `INSN_WRITE`\ninstructions are supposed to be able read or write multiple samples,\nindicated by the `insn->n` value, but `insn_rw_emulate_bits()` currently\nonly handles a single sample.  For `INSN_READ`, the comedi core will\ncopy `insn->n` samples back to user-space.  (That triggered KASAN\nkernel-infoleak errors when `insn->n` was greater than 1, but that is\nbeing fixed more generally elsewhere in the comedi core.)\n\nMake `insn_rw_emulate_bits()` either handle `insn->n` samples, or return\nan error, to conform to the general expectation for `INSN_READ` and\n`INSN_WRITE` handlers.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.149",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-39686"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ab77e85bd3bc006ef40738f26f446a660813da44"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ae8bc1f07bcb31b8636420e03d1f9c3df6219a2b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/842f307a1d115b24f2bcb2415c4e344f11f55930"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/92352ed2f9ac422181e381c2430c2d0dfb46faa0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/dc0a2f142d655700db43de90cb6abf141b73d908"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7afba9221f70d4cbce0f417c558879cba0eb5e66"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-12T04:54:46Z"
  }
}