CVE-2026-31598

Estado: ModificadaAlta (7.5)—

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

ocfs2: fix possible deadlock between unlink and dio_end_io_write

ocfs2_unlink takes orphan dir inode_lock first and then ip_alloc_sem, while in ocfs2_dio_end_io_write, it acquires these locks in reverse order. This creates an ABBA lock ordering violation on lock classes ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE] and ocfs2_file_ip_alloc_sem_key.

Since ip_alloc_sem is to protect allocation changes, which is unrelated with operations in ocfs2_del_inode_from_orphan. So move ocfs2_del_inode_from_orphan out of ip_alloc_sem to fix the deadlock.

Detalles técnicos trazas, registros y código del informe original

Lock Chain #0 (orphan dir inode_lock -> ip_alloc_sem):
ocfs2_unlink
  ocfs2_prepare_orphan_dir
    ocfs2_lookup_lock_orphan_dir
      inode_lock(orphan_dir_inode) <- lock A
    __ocfs2_prepare_orphan_dir
      ocfs2_prepare_dir_for_insert
        ocfs2_extend_dir
	  ocfs2_expand_inline_dir
	    down_write(&oi->ip_alloc_sem) <- Lock B

Lock Chain #1 (ip_alloc_sem -> orphan dir inode_lock):
ocfs2_dio_end_io_write
  down_write(&oi->ip_alloc_sem) <- Lock B
  ocfs2_del_inode_from_orphan()
    inode_lock(orphan_dir_inode) <- Lock A

Deadlock Scenario:
  CPU0 (unlink)                     CPU1 (dio_end_io_write)
  ------                            ------
  inode_lock(orphan_dir_inode)
                                    down_write(ip_alloc_sem)
  down_write(ip_alloc_sem)
                                    inode_lock(orphan_dir_inode)

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: 0.62%
Percentil entre todas las CVEs puntuadas: 48
Fecha de la puntuación: 5/10/2026

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 access60 %
Impacto principalT1499 Endpoint Denial of Serviceimpact55 %

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ 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

CWE-667

Referencias

JSON original (NVD)

Mostrar

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: fix possible deadlock between unlink and dio_end_io_write\n\nocfs2_unlink takes orphan dir inode_lock first and then ip_alloc_sem,\nwhile in ocfs2_dio_end_io_write, it acquires these locks in reverse order.\nThis creates an ABBA lock ordering violation on lock classes\nocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE] and\nocfs2_file_ip_alloc_sem_key.\n\nLock Chain #0 (orphan dir inode_lock -> ip_alloc_sem):\nocfs2_unlink\n  ocfs2_prepare_orphan_dir\n    ocfs2_lookup_lock_orphan_dir\n      inode_lock(orphan_dir_inode) <- lock A\n    __ocfs2_prepare_orphan_dir\n      ocfs2_prepare_dir_for_insert\n        ocfs2_extend_dir\n\t  ocfs2_expand_inline_dir\n\t    down_write(&oi->ip_alloc_sem) <- Lock B\n\nLock Chain #1 (ip_alloc_sem -> orphan dir inode_lock):\nocfs2_dio_end_io_write\n  down_write(&oi->ip_alloc_sem) <- Lock B\n  ocfs2_del_inode_from_orphan()\n    inode_lock(orphan_dir_inode) <- Lock A\n\nDeadlock Scenario:\n  CPU0 (unlink)                     CPU1 (dio_end_io_write)\n  ------                            ------\n  inode_lock(orphan_dir_inode)\n                                    down_write(ip_alloc_sem)\n  down_write(ip_alloc_sem)\n                                    inode_lock(orphan_dir_inode)\n\nSince ip_alloc_sem is to protect allocation changes, which is unrelated\nwith operations in ocfs2_del_inode_from_orphan.  So move\nocfs2_del_inode_from_orphan out of ip_alloc_sem to fix the deadlock."
    }
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