FKIE_CVE-2026-74499

Vulnerability from fkie_nvd - Published: 2026-08-15 13:17 - Updated: 2026-08-19 17:21
Severity
Summary
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 buf_end = ep->max_transfer - MAX_AKAI_SYSEX_LEN - 1; 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. 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>
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/00cc659a42ac4e94ec880fae2c9bf22fce69c2e8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0970274613fb463d376211450cab066d34ebfe6a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/29a4c29943631301e85f5e9d10f25741bd78e7ba
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2b7a0f330dd90dd1a7657cec0db019ee1efa4372
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/78dfdeb8d2065524ed5928d6470bf3d3244d1009
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9b22a5c8310b0d55d04f5f0159b913a2fb8b444f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b5305a0d0bb8e90a6fc9f88270d5f6c9b8c40081
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ce949d66607cfb000b8d8d84f80f35a886e72683
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "sound/usb/midi.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "78dfdeb8d2065524ed5928d6470bf3d3244d1009",
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "versionType": "git"
            },
            {
              "lessThan": "00cc659a42ac4e94ec880fae2c9bf22fce69c2e8",
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "versionType": "git"
            },
            {
              "lessThan": "ce949d66607cfb000b8d8d84f80f35a886e72683",
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "versionType": "git"
            },
            {
              "lessThan": "29a4c29943631301e85f5e9d10f25741bd78e7ba",
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "versionType": "git"
            },
            {
              "lessThan": "9b22a5c8310b0d55d04f5f0159b913a2fb8b444f",
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "versionType": "git"
            },
            {
              "lessThan": "b5305a0d0bb8e90a6fc9f88270d5f6c9b8c40081",
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "versionType": "git"
            },
            {
              "lessThan": "2b7a0f330dd90dd1a7657cec0db019ee1efa4372",
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "versionType": "git"
            },
            {
              "lessThan": "0970274613fb463d376211450cab066d34ebfe6a",
              "status": "affected",
              "version": "4434ade8c9334a3ab975d8993de456f06841899e",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "sound/usb/midi.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.35"
            },
            {
              "lessThan": "2.6.35",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.151",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.103",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "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-\u003emax_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-\u003etransfer_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 \u003cbaul.lee@xbow.com\u003e"
    }
  ],
  "id": "CVE-2026-74499",
  "lastModified": "2026-08-19T17:21:07.360",
  "metrics": {},
  "published": "2026-08-15T13:17:54.863",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "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"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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