CVE-2026-64479
In the Linux kernel, the following vulnerability has been resolved:
ALSA: seq: Fix uninitialised heap leak in snd_seq_event_dup()
snd_seq_event_dup() copies an incoming event into a pool cell and, in the UMP-enabled build, clears the trailing cell->ump.raw.extra word that the memcpy() did not cover. The guard deciding whether to clear it compares the copied size against sizeof(cell->event):
For a legacy (non-UMP) event, size == sizeof(struct snd_seq_event) == sizeof(cell->event), so the condition is false and the extra word keeps stale data. The cell pool is allocated with kvmalloc() (not zeroed) and cells are reused via a free list, so that word holds uninitialised heap or leftover event data.
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When such a cell is delivered to a UMP client (client->midi_version > 0) that set SNDRV_SEQ_FILTER_NO_CONVERT -- so the legacy event reaches it unconverted -- snd_seq_read() reads it out as the larger struct snd_seq_ump_event and copies the stale word to user space, a 4-byte kernel heap infoleak to an unprivileged /dev/snd/seq client.
Compare against sizeof(cell->ump) instead, so the trailing word is zeroed for every event shorter than the UMP cell.
Detalles técnicos trazas, registros y código del informe original
memcpy(&cell->ump, event, size); if (size < sizeof(cell->event)) cell->ump.raw.extra = 0;
CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.21%
- Percentil entre todas las CVEs puntuadas: 11
- Fecha de la puntuación: 6/10/2026
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
- https://git.kernel.org/stable/c/435990e25bf1f4af3e6df12a6fbfd1f7ba4a97d4
- https://git.kernel.org/stable/c/651ba82fe2a144bc7356d940bfd235c3810b0549
- https://git.kernel.org/stable/c/6ded42615fa1f4949925afd0a8a9e1ab3bf96202
- https://git.kernel.org/stable/c/a224c84e5d3d35708c082c84ad12d81d90762195
- https://git.kernel.org/stable/c/d7649aa11089a93ea2285c210397aa67e5800766
- https://git.kernel.org/stable/c/ea672a9f6cc38f06fe69dd2c257ef8a3d4db179a
- https://git.kernel.org/stable/c/fb1aa5082847b98f44f9c6272aee9d0dca9244f0
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-64479",
"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": "6389f2c135311c4ce7c08c3b29145c8f95aacf1f",
"lessThan": "d7649aa11089a93ea2285c210397aa67e5800766",
"versionType": "git"
},
{
"status": "affected",
"version": "d7e2ce72833bb23a82b4201fbed7214cc04a4a8c",
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"versionType": "git"
},
{
"status": "affected",
"version": "46397622a3fa8372b8fda0f04b33d16923b03b1b",
"lessThan": "ea672a9f6cc38f06fe69dd2c257ef8a3d4db179a",
"versionType": "git"
},
{
"status": "affected",
"version": "46397622a3fa8372b8fda0f04b33d16923b03b1b",
"lessThan": "fb1aa5082847b98f44f9c6272aee9d0dca9244f0",
"versionType": "git"
},
{
"status": "affected",
"version": "46397622a3fa8372b8fda0f04b33d16923b03b1b",
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"versionType": "git"
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{
"status": "affected",
"version": "46397622a3fa8372b8fda0f04b33d16923b03b1b",
"lessThan": "6ded42615fa1f4949925afd0a8a9e1ab3bf96202",
"versionType": "git"
},
{
"status": "affected",
"version": "46397622a3fa8372b8fda0f04b33d16923b03b1b",
"lessThan": "435990e25bf1f4af3e6df12a6fbfd1f7ba4a97d4",
"versionType": "git"
}
],
"programFiles": [
"sound/core/seq/seq_memory.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.5"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.5",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.96",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.4",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"sound/core/seq/seq_memory.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-07-25T10:17:33.493",
"references": [
{
"url": "https://git.kernel.org/stable/c/435990e25bf1f4af3e6df12a6fbfd1f7ba4a97d4",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/651ba82fe2a144bc7356d940bfd235c3810b0549",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/6ded42615fa1f4949925afd0a8a9e1ab3bf96202",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/a224c84e5d3d35708c082c84ad12d81d90762195",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/d7649aa11089a93ea2285c210397aa67e5800766",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/ea672a9f6cc38f06fe69dd2c257ef8a3d4db179a",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/fb1aa5082847b98f44f9c6272aee9d0dca9244f0",
"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 uninitialised heap leak in snd_seq_event_dup()\n\nsnd_seq_event_dup() copies an incoming event into a pool cell and, in\nthe UMP-enabled build, clears the trailing cell->ump.raw.extra word that\nthe memcpy() did not cover. The guard deciding whether to clear it\ncompares the copied size against sizeof(cell->event):\n\n\tmemcpy(&cell->ump, event, size);\n\tif (size < sizeof(cell->event))\n\t\tcell->ump.raw.extra = 0;\n\nFor a legacy (non-UMP) event, size == sizeof(struct snd_seq_event) ==\nsizeof(cell->event), so the condition is false and the extra word keeps\nstale data. The cell pool is allocated with kvmalloc() (not zeroed) and\ncells are reused via a free list, so that word holds uninitialised heap\nor leftover event data.\n\nWhen such a cell is delivered to a UMP client (client->midi_version > 0)\nthat set SNDRV_SEQ_FILTER_NO_CONVERT -- so the legacy event reaches it\nunconverted -- snd_seq_read() reads it out as the larger struct\nsnd_seq_ump_event and copies the stale word to user space, a 4-byte\nkernel heap infoleak to an unprivileged /dev/snd/seq client.\n\nCompare against sizeof(cell->ump) instead, so the trailing word is zeroed\nfor every event shorter than the UMP cell."
}
],
"lastModified": "2026-08-17T05:17:53.653",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}