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CVE-2026-74278

Estado: RecibidaSin puntuar—

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

ALSA: seq: Fix kernel heap address leak in bounce_error_event()

The comment above bounce_error_event() documents that user clients should receive SNDRV_SEQ_EVENT_BOUNCE with the original event embedded as variable-length data, while kernel clients should receive SNDRV_SEQ_EVENT_KERNEL_ERROR with a quoted kernel pointer.

However, the implementation unconditionally uses SNDRV_SEQ_EVENT_KERNEL_ERROR with data.quote.event set to the raw struct snd_seq_event pointer for all clients. When a bounce error event is delivered to a USER_CLIENT via snd_seq_read(), the kernel heap address in data.quote.event is exposed to userspace through copy_to_user() in the fixed-length branch.

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This is a distinct leak path from the one addressed by commit 705dd6dcbc0e ("ALSA: seq: Clear variable event pointer on read"), which sanitizes data.ext.ptr in the variable-length branch of snd_seq_read(). The bounce_error_event() leak uses fixed-length events that take the else branch where no sanitization occurs.

Differentiate the bounce event by client type. For USER_CLIENT, send SNDRV_SEQ_EVENT_BOUNCE with SNDRV_SEQ_EVENT_LENGTH_VARIABLE and data.ext pointing to the original event. The variable-length path in snd_seq_event_dup() copies the event data into chained cells, and snd_seq_expand_var_event() copies only the content -- never the pointer -- to userspace. For KERNEL_CLIENT, keep the existing SNDRV_SEQ_EVENT_KERNEL_ERROR behavior with the quoted pointer.

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.

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-74278",
  "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": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "93d260ce43a81df579c98bee92b91316df9c1c57",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "dae23c545eb5a2be3b27a82fd0f611894fb8ab69",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "0527a56cb327021cb73167cfddf0e49efa043500",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "lessThan": "efc86691e4d8083d9e380ea95042c2cf679f65fd",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "sound/core/seq/seq_clientmgr.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.12"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "2.6.12",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "sound/core/seq/seq_clientmgr.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T06:22:27.213",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/0527a56cb327021cb73167cfddf0e49efa043500",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/93d260ce43a81df579c98bee92b91316df9c1c57",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/dae23c545eb5a2be3b27a82fd0f611894fb8ab69",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/efc86691e4d8083d9e380ea95042c2cf679f65fd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: Fix kernel heap address leak in bounce_error_event()\n\nThe comment above bounce_error_event() documents that user clients\nshould receive SNDRV_SEQ_EVENT_BOUNCE with the original event embedded\nas variable-length data, while kernel clients should receive\nSNDRV_SEQ_EVENT_KERNEL_ERROR with a quoted kernel pointer.\n\nHowever, the implementation unconditionally uses\nSNDRV_SEQ_EVENT_KERNEL_ERROR with data.quote.event set to the raw\nstruct snd_seq_event pointer for all clients.  When a bounce error\nevent is delivered to a USER_CLIENT via snd_seq_read(), the kernel\nheap address in data.quote.event is exposed to userspace through\ncopy_to_user() in the fixed-length branch.\n\nThis is a distinct leak path from the one addressed by commit\n705dd6dcbc0e (\"ALSA: seq: Clear variable event pointer on read\"),\nwhich sanitizes data.ext.ptr in the variable-length branch of\nsnd_seq_read().  The bounce_error_event() leak uses fixed-length\nevents that take the else branch where no sanitization occurs.\n\nDifferentiate the bounce event by client type.  For USER_CLIENT,\nsend SNDRV_SEQ_EVENT_BOUNCE with SNDRV_SEQ_EVENT_LENGTH_VARIABLE\nand data.ext pointing to the original event.  The variable-length\npath in snd_seq_event_dup() copies the event data into chained\ncells, and snd_seq_expand_var_event() copies only the content --\nnever the pointer -- to userspace.  For KERNEL_CLIENT, keep the\nexisting SNDRV_SEQ_EVENT_KERNEL_ERROR behavior with the quoted\npointer."
    }
  ],
  "lastModified": "2026-08-17T06:19:21.510",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}