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CVE-2026-31694

Estado: ModificadaAlta (7.8)—

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

fuse: reject oversized dirents in page cache

fuse_add_dirent_to_cache() computes a serialized dirent size from the server-controlled namelen field and copies the dirent into a single page-cache page. The existing logic only checks whether the dirent fits in the remaining space of the current page and advances to a fresh page if not. It never checks whether the dirent itself exceeds PAGE_SIZE.

As a result, a malicious FUSE server can return a dirent with namelen=4095, producing a serialized record size of 4120 bytes. On 4 KiB page systems this causes memcpy() to overflow the cache page by 24 bytes into the following kernel page.

Leer descripción completaMostrar menos

Reject dirents that cannot fit in a single page before copying them into the readdir cache.

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) sin interacción del usuario en kernel Linux. Un servidor FUSE malicioso causa desbordamiento de búfer en caché de páginas, permitiendo lectura de memoria del kernel (C:H) y denegación de servicio (A:H).

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 ProgramFilter Network TrafficExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate Software

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\nfuse: reject oversized dirents in page cache\n\nfuse_add_dirent_to_cache() computes a serialized dirent size from the\nserver-controlled namelen field and copies the dirent into a single\npage-cache page. The existing logic only checks whether the dirent fits\nin the remaining space of the current page and advances to a fresh page\nif not. It never checks whether the dirent itself exceeds PAGE_SIZE.\n\nAs a result, a malicious FUSE server can return a dirent with\nnamelen=4095, producing a serialized record size of 4120 bytes. On 4 KiB\npage systems this causes memcpy() to overflow the cache page by 24 bytes\ninto the following kernel page.\n\nReject dirents that cannot fit in a single page before copying them into\nthe readdir cache."
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