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CVE-2025-39905

Estado: ModificadaAlta (7)—

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

net: phylink: add lock for serializing concurrent pl->phydev writes with resolver

Currently phylink_resolve() protects itself against concurrent phylink_bringup_phy() or phylink_disconnect_phy() calls which modify pl->phydev by relying on pl->state_mutex.

The problem is that in phylink_resolve(), pl->state_mutex is in a lock inversion state with pl->phydev->lock. So pl->phydev->lock needs to be acquired prior to pl->state_mutex. But that requires dereferencing pl->phydev in the first place, and without pl->state_mutex, that is racy.

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Hence the reason for the extra lock. Currently it is redundant, but it will serve a functional purpose once mutex_lock(&phy->lock) will be moved outside of the mutex_lock(&pl->state_mutex) section.

Another alternative considered would have been to let phylink_resolve() acquire the rtnl_mutex, which is also held when phylink_bringup_phy() and phylink_disconnect_phy() are called. But since phylink_disconnect_phy() runs under rtnl_lock(), it would deadlock with phylink_resolve() when calling flush_work(&pl->resolve). Additionally, it would have been undesirable because it would have unnecessarily blocked many other call paths as well in the entire kernel, so the smaller-scoped lock was preferred.

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.

CWE-362 (race condition) en kernel de Linux con acceso local (AV:L) y privilegios limitados (PR:L) permite escalada de privilegios mediante condición de carrera en phylink, confirmado por pista de reglas.

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 Software

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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