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CVE-2025-21915

Estado: ModificadaAlta (7.8)—

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

cdx: Fix possible UAF error in driver_override_show()

Fixed a possible UAF problem in driver_override_show() in drivers/cdx/cdx.c

This function driver_override_show() is part of DEVICE_ATTR_RW, which includes both driver_override_show() and driver_override_store(). These functions can be executed concurrently in sysfs.

The driver_override_store() function uses driver_set_override() to update the driver_override value, and driver_set_override() internally locks the device (device_lock(dev)).

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If driver_override_show() reads cdx_dev->driver_override without locking, it could potentially access a freed pointer if driver_override_store() frees the string concurrently. This could lead to printing a kernel address, which is a security risk since DEVICE_ATTR can be read by all users.

Additionally, a similar pattern is used in drivers/amba/bus.c, as well as many other bus drivers, where device_lock() is taken in the show function, and it has been working without issues.

This potential bug was detected by our experimental static analysis tool, which analyzes locking APIs and paired functions to identify data races and atomicity violations.

CVSS

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).

🎯 Técnicas ATT&CK

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

Vulnerabilidad local (AV:L/PR:L) que permite lectura de memoria del kernel (dirección de kernel) mediante condición de carrera en sysfs sin interacción del usuario. CWE-416 (UAF) en contexto local.

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

Threat Intelligence ProgramExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate SoftwareData Loss Prevention

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncdx: Fix possible UAF error in driver_override_show()\n\nFixed a possible UAF problem in driver_override_show() in drivers/cdx/cdx.c\n\nThis function driver_override_show() is part of DEVICE_ATTR_RW, which\nincludes both driver_override_show() and driver_override_store().\nThese functions can be executed concurrently in sysfs.\n\nThe driver_override_store() function uses driver_set_override() to\nupdate the driver_override value, and driver_set_override() internally\nlocks the device (device_lock(dev)). If driver_override_show() reads\ncdx_dev->driver_override without locking, it could potentially access\na freed pointer if driver_override_store() frees the string\nconcurrently. This could lead to printing a kernel address, which is a\nsecurity risk since DEVICE_ATTR can be read by all users.\n\nAdditionally, a similar pattern is used in drivers/amba/bus.c, as well\nas many other bus drivers, where device_lock() is taken in the show\nfunction, and it has been working without issues.\n\nThis potential bug was detected by our experimental static analysis\ntool, which analyzes locking APIs and paired functions to identify\ndata races and atomicity violations."
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      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: cdx: Se corrige un posible error de UAF en driver_override_show() Se corrigió un posible problema de UAF en driver_override_show() en drivers/cdx/cdx.c Esta función driver_override_show() es parte de DEVICE_ATTR_RW, que incluye tanto driver_override_show() como driver_override_store(). Estas funciones se pueden ejecutar simultáneamente en sysfs. La función driver_override_store() usa driver_set_override() para actualizar el valor de driver_override, y driver_set_override() bloquea internamente el dispositivo (device_lock(dev)). Si driver_override_show() lee cdx_dev->driver_override sin bloquear, podría acceder potencialmente a un puntero liberado si driver_override_store() libera la cadena simultáneamente. Esto podría llevar a imprimir una dirección del kernel, lo cual es un riesgo de seguridad ya que DEVICE_ATTR puede ser leído por todos los usuarios. Además, se utiliza un patrón similar en drivers/amba/bus.c, así como en muchos otros controladores de bus, donde device_lock() se utiliza en la función show y ha funcionado sin problemas. Este posible error fue detectado por nuestra herramienta experimental de análisis estático, que analiza las API de bloqueo y las funciones emparejadas para identificar carreras de datos y violaciones de atomicidad."
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