CVE-2026-53026

Estado: AnalizadaAlta (7.5)—

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

NFSD: fix nfs4_file access extra count in nfsd4_add_rdaccess_to_wrdeleg

In nfsd4_add_rdaccess_to_wrdeleg, if fp->fi_fds[O_RDONLY] is already set by another thread, __nfs4_file_get_access should not be called to increment the nfs4_file access count since that was already done by the thread that added READ access to the file. The extra fi_access count in nfs4_file can prevent the corresponding nfsd_file from being freed.

When stopping nfs-server service, these extra access counts trigger a BUG in kmem_cache_destroy() that shows nfsd_file object remaining on __kmem_cache_shutdown.

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This problem can be reproduced by running the Git project's test suite over NFS.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Puntuación base: 7.5

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.61%
Percentil entre todas las CVEs puntuadas: 47
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.

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access40 %
Impacto principalT1499.004 Application or System Exploitationimpact75 %
Impacto secundarioT1499 Endpoint Denial of Serviceimpact60 %

Vulnerabilidad de DoS en NFSD (demonio NFS remoto accesible en red sin autenticación requerida, AV:N/PR:N), causada por conteo incorrecto de accesos que previene liberación de memoria, disparando BUG en kmem_cache_destroy al detener el servicio.

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 Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

NVD-CWE-noinfo

Referencias

JSON original (NVD)

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