CVE-2025-39994

Estado: AplazadaAlta (7.3)—

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

media: tuner: xc5000: Fix use-after-free in xc5000_release

The original code uses cancel_delayed_work() in xc5000_release(), which does not guarantee that the delayed work item timer_sleep has fully completed if it was already running. This leads to use-after-free scenarios where xc5000_release() may free the xc5000_priv while timer_sleep is still active and attempts to dereference the xc5000_priv.

A typical race condition is illustrated below:

Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure that the timer_sleep is properly canceled before the xc5000_priv memory is deallocated.

Leer descripción completaMostrar menos

A deadlock concern was considered: xc5000_release() is called in a process context and is not holding any locks that the timer_sleep work item might also need. Therefore, the use of the _sync() variant is safe here.

This bug was initially identified through static analysis.

[hverkuil: fix typo in Subject: tunner -> tuner]

Detalles técnicos trazas, registros y código del informe original

CPU 0 (release thread)                 | CPU 1 (delayed work callback)
xc5000_release()                       | xc5000_do_timer_sleep()
  cancel_delayed_work()                |
  hybrid_tuner_release_state(priv)     |
    kfree(priv)                        |
                                       |   priv = container_of() // UAF

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Puntuación base: 7.3

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.15%
Percentil entre todas las CVEs puntuadas: 4
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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1203 Exploitation for Client Executionexecution45 %
Impacto principalT1499.004 Application or System Exploitationimpact35 %

AV:L/UI:R sugiere ejecución en cliente (T1203). Use-after-free puede causar DoS o corrupción; sin evidencia de RCE o lectura de datos en el texto.

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

Filter Network Traffic Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

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

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

Mostrar

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  "id": "CVE-2025-39994",
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          "version": "3.1",
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    }
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  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: tuner: xc5000: Fix use-after-free in xc5000_release\n\nThe original code uses cancel_delayed_work() in xc5000_release(), which\ndoes not guarantee that the delayed work item timer_sleep has fully\ncompleted if it was already running. This leads to use-after-free scenarios\nwhere xc5000_release() may free the xc5000_priv while timer_sleep is still\nactive and attempts to dereference the xc5000_priv.\n\nA typical race condition is illustrated below:\n\nCPU 0 (release thread)                 | CPU 1 (delayed work callback)\nxc5000_release()                       | xc5000_do_timer_sleep()\n  cancel_delayed_work()                |\n  hybrid_tuner_release_state(priv)     |\n    kfree(priv)                        |\n                                       |   priv = container_of() // UAF\n\nReplace cancel_delayed_work() with cancel_delayed_work_sync() to ensure\nthat the timer_sleep is properly canceled before the xc5000_priv memory\nis deallocated.\n\nA deadlock concern was considered: xc5000_release() is called in a process\ncontext and is not holding any locks that the timer_sleep work item might\nalso need. Therefore, the use of the _sync() variant is safe here.\n\nThis bug was initially identified through static analysis.\n\n[hverkuil: fix typo in Subject: tunner -> tuner]"
    }
  ],
  "lastModified": "2026-07-30T06:24:05.577",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}