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CVE-2026-74499

Estado: RecibidaSin puntuar—

In the Linux kernel, the following vulnerability has been resolved:

ALSA: usb-audio: fix OOB write in snd_usbmidi_akai_output()

snd_usbmidi_akai_output() computes its fill-loop bound

as a signed int, so a small device-advertised bulk-OUT max_transfer makes buf_end negative. The loop guard then compares the u32 urb->transfer_buffer_length against that negative int: the usual arithmetic conversion turns buf_end into a large unsigned value, so the guard stays true and each iteration keeps appending SysEx framing and payload bytes past the end of the URB transfer buffer, which is only max_transfer bytes long.

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A USB device that advertises a tiny bulk-OUT endpoint can therefore trigger an attacker-length- and content-controlled heap out-of-bounds write when a process writes to the created /dev/snd/midiC*D* node.

Return early when there is no room for even one SysEx, so the loop is never entered with a bound that would wrap. The loop is the last statement of the function, so bailing out is equivalent to it not running.

Discovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>

Detalles técnicos trazas, registros y código del informe original
	buf_end = ep->max_transfer - MAX_AKAI_SYSEX_LEN - 1;

CVSS

NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-74499",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "lessThan": "78dfdeb8d2065524ed5928d6470bf3d3244d1009",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "lessThan": "00cc659a42ac4e94ec880fae2c9bf22fce69c2e8",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "lessThan": "ce949d66607cfb000b8d8d84f80f35a886e72683",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "lessThan": "29a4c29943631301e85f5e9d10f25741bd78e7ba",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "lessThan": "9b22a5c8310b0d55d04f5f0159b913a2fb8b444f",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "lessThan": "b5305a0d0bb8e90a6fc9f88270d5f6c9b8c40081",
              "versionType": "git"
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            {
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              "versionType": "git"
            },
            {
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              "lessThan": "0970274613fb463d376211450cab066d34ebfe6a",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "sound/usb/midi.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.35"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "2.6.35",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.151",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.103",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "sound/usb/midi.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T13:17:54.863",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/00cc659a42ac4e94ec880fae2c9bf22fce69c2e8",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/0970274613fb463d376211450cab066d34ebfe6a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/29a4c29943631301e85f5e9d10f25741bd78e7ba",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/2b7a0f330dd90dd1a7657cec0db019ee1efa4372",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/78dfdeb8d2065524ed5928d6470bf3d3244d1009",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9b22a5c8310b0d55d04f5f0159b913a2fb8b444f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b5305a0d0bb8e90a6fc9f88270d5f6c9b8c40081",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ce949d66607cfb000b8d8d84f80f35a886e72683",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: usb-audio: fix OOB write in snd_usbmidi_akai_output()\n\nsnd_usbmidi_akai_output() computes its fill-loop bound\n\n\tbuf_end = ep->max_transfer - MAX_AKAI_SYSEX_LEN - 1;\n\nas a signed int, so a small device-advertised bulk-OUT max_transfer\nmakes buf_end negative.  The loop guard then compares the u32\nurb->transfer_buffer_length against that negative int: the usual\narithmetic conversion turns buf_end into a large unsigned value, so the\nguard stays true and each iteration keeps appending SysEx framing and\npayload bytes past the end of the URB transfer buffer, which is only\nmax_transfer bytes long.\n\nA USB device that advertises a tiny bulk-OUT endpoint can therefore\ntrigger an attacker-length- and content-controlled heap out-of-bounds\nwrite when a process writes to the created /dev/snd/midiC*D* node.\n\nReturn early when there is no room for even one SysEx, so the loop is\nnever entered with a bound that would wrap.  The loop is the last\nstatement of the function, so bailing out is equivalent to it not\nrunning.\n\nDiscovered by XBOW, triaged by Baul Lee <baul.lee@xbow.com>"
    }
  ],
  "lastModified": "2026-08-19T17:21:07.360",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}