CVE-2026-43076

Estado: ModificadaAlta (7.8)—

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

ocfs2: validate inline data i_size during inode read

When reading an inode from disk, ocfs2_validate_inode_block() performs various sanity checks but does not validate the size of inline data. If the filesystem is corrupted, an inode's i_size can exceed the actual inline data capacity (id_count).

This causes ocfs2_dir_foreach_blk_id() to iterate beyond the inline data buffer, triggering a use-after-free when accessing directory entries from freed memory.

Fix by adding a validation check in ocfs2_validate_inode_block() to ensure inodes with inline data have i_size <= id_count. This catches the corruption early during inode read and prevents all downstream code from operating on invalid data.

Detalles técnicos trazas, registros y código del informe original

In the syzbot report:
  - i_size was 1099511627576 bytes (~1TB)
  - Actual inline data capacity (id_count) is typically <256 bytes
  - A garbage rec_len (54648) caused ctx->pos to jump out of bounds
  - This triggered a UAF in ocfs2_check_dir_entry()

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.18%
Percentil entre todas las CVEs puntuadas: 7
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 Executionexecution75 %
Impacto principalT1059 Command and Scripting Interpreterexecution60 %
Impacto secundarioT1499.004 Application or System Exploitationimpact70 %

AV:L + UI:R → T1203 (ejecución en cliente). Corrupción de inode causa UAF → ejecución de código (T1059) o DoS por crash del kernel (T1499.004).

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

Restrict Web-Based Content Privileged Account Management Limit Software Installation Filter Network Traffic Execution Prevention Behavior Prevention on Endpoint

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-416

Referencias

JSON original (NVD)

Mostrar

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