CVE-2026-53041

Estado: AnalizadaAlta (7.1)—

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

ocfs2: fix listxattr handling when the buffer is full

[BUG] If an OCFS2 inode has both inline and block-based xattrs, listxattr() can return a size larger than the caller's buffer when the inline names consume that buffer exactly.

[CAUSE] Commit 936b8834366e ("ocfs2: Refactor xattr list and remove ocfs2_xattr_handler().") replaced the old per-handler list accounting with ocfs2_xattr_list_entry(), but it kept using size == 0 to detect probe mode.

That assumption stops being true once ocfs2_listxattr() finishes the inline-xattr pass.

Leer descripción completaMostrar menos

If the inline names fill the caller buffer exactly, the block-xattr pass runs with a non-NULL buffer and a remaining size of zero. ocfs2_xattr_list_entry() then skips the bounds check, keeps counting block names, and returns a positive size larger than the supplied buffer.

[FIX] Detect probe mode by testing whether the destination buffer pointer is NULL instead of whether the remaining size is zero.

That restores the pre-refactor behavior and matches the OCFS2 getxattr helpers. Once the remaining buffer reaches zero while more names are left, the block-xattr pass now returns -ERANGE instead of reporting a size larger than the allocated list buffer.

Detalles técnicos trazas, registros y código del informe original

kernel BUG at mm/usercopy.c:102!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
RIP: 0010:usercopy_abort+0xb7/0xd0 mm/usercopy.c:102
Call Trace:
 __check_heap_object+0xe3/0x120 mm/slub.c:8243
 check_heap_object mm/usercopy.c:196 [inline]
 __check_object_size mm/usercopy.c:250 [inline]
 __check_object_size+0x5c5/0x780 mm/usercopy.c:215
 check_object_size include/linux/ucopysize.h:22 [inline]
 check_copy_size include/linux/ucopysize.h:59 [inline]
 copy_to_user include/linux/uaccess.h:219 [inline]
 listxattr+0xb0/0x170 fs/xattr.c:926
 filename_listxattr fs/xattr.c:958 [inline]
 path_listxattrat+0x137/0x320 fs/xattr.c:988
 __do_sys_listxattr fs/xattr.c:1001 [inline]
 __se_sys_listxattr fs/xattr.c:998 [inline]
 __x64_sys_listxattr+0x7f/0xd0 fs/xattr.c:998
 ...

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Puntuación base: 7.1

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.17%
Percentil entre todas las CVEs puntuadas: 5
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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1499.004 Application or System Exploitationimpact75 %

Buffer overflow (CWE-787) en modo local (AV:L, PR:L) sin interacción del usuario, típico de escalada de privilegios. El kernel crash (usercopy_abort) y BUG indica negación de servicio; potencial para elevar privilegios vía heap corruption.

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 Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-787

Referencias

JSON original (NVD)

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      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: fix listxattr handling when the buffer is full\n\n[BUG]\nIf an OCFS2 inode has both inline and block-based xattrs, listxattr()\ncan return a size larger than the caller's buffer when the inline names\nconsume that buffer exactly.\n\nkernel BUG at mm/usercopy.c:102!\nOops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\nRIP: 0010:usercopy_abort+0xb7/0xd0 mm/usercopy.c:102\nCall Trace:\n __check_heap_object+0xe3/0x120 mm/slub.c:8243\n check_heap_object mm/usercopy.c:196 [inline]\n __check_object_size mm/usercopy.c:250 [inline]\n __check_object_size+0x5c5/0x780 mm/usercopy.c:215\n check_object_size include/linux/ucopysize.h:22 [inline]\n check_copy_size include/linux/ucopysize.h:59 [inline]\n copy_to_user include/linux/uaccess.h:219 [inline]\n listxattr+0xb0/0x170 fs/xattr.c:926\n filename_listxattr fs/xattr.c:958 [inline]\n path_listxattrat+0x137/0x320 fs/xattr.c:988\n __do_sys_listxattr fs/xattr.c:1001 [inline]\n __se_sys_listxattr fs/xattr.c:998 [inline]\n __x64_sys_listxattr+0x7f/0xd0 fs/xattr.c:998\n ...\n\n[CAUSE]\nCommit 936b8834366e (\"ocfs2: Refactor xattr list and remove\nocfs2_xattr_handler().\") replaced the old per-handler list accounting\nwith ocfs2_xattr_list_entry(), but it kept using size == 0 to detect\nprobe mode.\n\nThat assumption stops being true once ocfs2_listxattr() finishes the\ninline-xattr pass. If the inline names fill the caller buffer exactly,\nthe block-xattr pass runs with a non-NULL buffer and a remaining size of\nzero. ocfs2_xattr_list_entry() then skips the bounds check, keeps\ncounting block names, and returns a positive size larger than the\nsupplied buffer.\n\n[FIX]\nDetect probe mode by testing whether the destination buffer pointer is\nNULL instead of whether the remaining size is zero.\n\nThat restores the pre-refactor behavior and matches the OCFS2 getxattr\nhelpers. Once the remaining buffer reaches zero while more names are\nleft, the block-xattr pass now returns -ERANGE instead of reporting a\nsize larger than the allocated list buffer."
    }
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  "lastModified": "2026-07-14T19:33:34.350",
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