CVE-2026-89736
Estado: RecibidaAlta (7.8)—
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: u_audio: Fix use-after-free on sound card disconnect
g_audio_cleanup() invokes snd_card_free_when_closed() to initiate sound card teardown and immediately frees the underlying struct snd_uac_chip context. However, snd_card_free_when_closed() returns asynchronously while ALSA control elements (kctls) remain open in userspace.
When userspace control applications access or close these open file descriptors, kctl callbacks attempt to dereference kctl->private_data pointing to &uac->c_prm or &uac->p_prm within the freed uac structure, resulting in a use-after-free (UAF) memory corruption.
Leer descripción completaMostrar menos
Fix this issue by deferring the destruction of struct snd_uac_chip until all references to the ALSA sound card are released. Register a custom card->private_free callback (u_audio_card_free) during g_audio_setup() that frees uac and its associated playback/capture request and ring buffers only when the sound card reference count drops to zero.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Puntuación base: 7.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.17%
- Percentil entre todas las CVEs puntuadas: 6
- Fecha de la puntuación: 3/10/2026
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).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1068Exploitation for Privilege Escalationprivilege escalation85 % - Impacto principal
T1005Data from Local Systemcollection75 % - Impacto secundario
T1499.004Application or System Exploitationimpact70 %
Vulnerabilidad local de use-after-free en kernel Linux (AV:L, PR:L) que permite lectura de memoria y corrupción; acceso local con privilegios de usuario confirmado en vector CVSS.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
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/4e747c864a88537e18b1ffc19a1954c9686bb8e1
- https://git.kernel.org/stable/c/6f46762196f04464e1050a9ee94e72b917db9010
- https://git.kernel.org/stable/c/79a92896e2bb9471550c56fc23d8d93592f04c27
- https://git.kernel.org/stable/c/858965947081d10d41d9a1010a540d3d5eea958b
- https://git.kernel.org/stable/c/891a8d11f4d5eb50b2ce7570f4f98204a7a57493
- https://git.kernel.org/stable/c/a7ecd1a04f4f485d7be6443d0f0b2c61a800cb82
- https://git.kernel.org/stable/c/c74ff0b1a0fca53d3ac185873c87d6a719b30a47
- https://git.kernel.org/stable/c/f983793f03148b097977f200298db215cd2d4438
JSON original (NVD)
Mostrar
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"id": "CVE-2026-89736",
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"metrics": {
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{
"type": "Secondary",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"version": "3.1",
"baseScore": 7.8,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
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"published": "2026-09-11T20:20:04.077",
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: u_audio: Fix use-after-free on sound card disconnect\n\ng_audio_cleanup() invokes snd_card_free_when_closed() to initiate sound\ncard teardown and immediately frees the underlying struct snd_uac_chip\ncontext. However, snd_card_free_when_closed() returns asynchronously\nwhile ALSA control elements (kctls) remain open in userspace.\n\nWhen userspace control applications access or close these open file\ndescriptors, kctl callbacks attempt to dereference kctl->private_data\npointing to &uac->c_prm or &uac->p_prm within the freed uac structure,\nresulting in a use-after-free (UAF) memory corruption.\n\nFix this issue by deferring the destruction of struct snd_uac_chip until\nall references to the ALSA sound card are released. Register a custom\ncard->private_free callback (u_audio_card_free) during g_audio_setup()\nthat frees uac and its associated playback/capture request and ring\nbuffers only when the sound card reference count drops to zero."
}
],
"lastModified": "2026-09-14T13:19:22.700",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}