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CVE-2025-71110

Estado: AnalizadaAlta (7.8)—

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

mm/slub: reset KASAN tag in defer_free() before accessing freed memory

When CONFIG_SLUB_TINY is enabled, kfree_nolock() calls kasan_slab_free() before defer_free(). On ARM64 with MTE (Memory Tagging Extension), kasan_slab_free() poisons the memory and changes the tag from the original (e.g., 0xf3) to a poison tag (0xfe).

When defer_free() then tries to write to the freed object to build the deferred free list via llist_add(), the pointer still has the old tag, causing a tag mismatch and triggering a KASAN use-after-free report:

Fix this by calling kasan_reset_tag() before accessing the freed memory. This is safe because defer_free() is part of the allocator itself and is expected to manipulate freed memory for bookkeeping purposes.

Detalles técnicos trazas, registros y código del informe original
  BUG: KASAN: slab-use-after-free in defer_free+0x3c/0xbc mm/slub.c:6537
  Write at addr f3f000000854f020 by task kworker/u8:6/983
  Pointer tag: [f3], memory tag: [fe]

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.

AV:L PR:L sin interacción sugiere escalada local; CWE-416 (use-after-free) permite ejecución de código arbitrario desde contexto con privilegios de usuario.

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

Execution PreventionThreat Intelligence ProgramRestrict Web-Based ContentPrivileged Account ManagementLimit Software InstallationBehavior Prevention on Endpoint

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

Mostrar
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      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slub: reset KASAN tag in defer_free() before accessing freed memory\n\nWhen CONFIG_SLUB_TINY is enabled, kfree_nolock() calls kasan_slab_free()\nbefore defer_free(). On ARM64 with MTE (Memory Tagging Extension),\nkasan_slab_free() poisons the memory and changes the tag from the\noriginal (e.g., 0xf3) to a poison tag (0xfe).\n\nWhen defer_free() then tries to write to the freed object to build the\ndeferred free list via llist_add(), the pointer still has the old tag,\ncausing a tag mismatch and triggering a KASAN use-after-free report:\n\n  BUG: KASAN: slab-use-after-free in defer_free+0x3c/0xbc mm/slub.c:6537\n  Write at addr f3f000000854f020 by task kworker/u8:6/983\n  Pointer tag: [f3], memory tag: [fe]\n\nFix this by calling kasan_reset_tag() before accessing the freed memory.\nThis is safe because defer_free() is part of the allocator itself and is\nexpected to manipulate freed memory for bookkeeping purposes."
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      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nmm/slub: restablecer la etiqueta KASAN en defer_free() antes de acceder a la memoria liberada\n\nCuando CONFIG_SLUB_TINY está habilitado, kfree_nolock() llama a kasan_slab_free() antes de defer_free(). En ARM64 con MTE (Extensión de Etiquetado de Memoria), kasan_slab_free() envenena la memoria y cambia la etiqueta de la original (p. ej., 0xf3) a una etiqueta de envenenamiento (0xfe).\n\nCuando defer_free() intenta escribir en el objeto liberado para construir la lista de liberación diferida a través de llist_add(), el puntero todavía tiene la etiqueta antigua, causando una falta de coincidencia de etiquetas y desencadenando un informe KASAN de uso después de liberación:\n\n  ERROR: KASAN: uso después de liberación de slab en defer_free+0x3c/0xbc mm/slub.c:6537\n  Escritura en la dirección f3f000000854f020 por la tarea kworker/u8:6/983\n  Etiqueta del puntero: [f3], etiqueta de memoria: [fe]\n\nSolucionar esto llamando a kasan_reset_tag() antes de acceder a la memoria liberada. Esto es seguro porque defer_free() es parte del propio asignador y se espera que manipule la memoria liberada para fines de contabilidad."
    }
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  "lastModified": "2026-06-17T10:03:41.037",
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