CVE-2026-31406

Estado: AnalizadaAlta (7.8)—

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

xfrm: Fix work re-schedule after cancel in xfrm_nat_keepalive_net_fini()

After cancel_delayed_work_sync() is called from xfrm_nat_keepalive_net_fini(), xfrm_state_fini() flushes remaining states via __xfrm_state_delete(), which calls xfrm_nat_keepalive_state_updated() to re-schedule nat_keepalive_work.

The following is a simple race scenario:

To prevent this, cancel_delayed_work_sync() is replaced with disable_delayed_work_sync().

Detalles técnicos trazas, registros y código del informe original

           cpu0                             cpu1

cleanup_net() [Round 1]
  ops_undo_list()
    xfrm_net_exit()
      xfrm_nat_keepalive_net_fini()
        cancel_delayed_work_sync(nat_keepalive_work);
      xfrm_state_fini()
        xfrm_state_flush()
          xfrm_state_delete(x)
            __xfrm_state_delete(x)
              xfrm_nat_keepalive_state_updated(x)
                schedule_delayed_work(nat_keepalive_work);
  rcu_barrier();
  net_complete_free();
  net_passive_dec(net);
    llist_add(&net->defer_free_list, &defer_free_list);

cleanup_net() [Round 2]
  rcu_barrier();
  net_complete_free()
    kmem_cache_free(net_cachep, net);
                                     nat_keepalive_work()
                                       // on freed net

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/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: 6
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.

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

Vulnerabilidad local (AV:L, PR:L) sin interacción: escalada de privilegios por race condition en liberación de memoria. Use-after-free en nat_keepalive_work permite ejecución con contexto elevado (C:H, I:H, A:H). Impacto DoS por corrupción de memoria y potencial EOP.

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

NVD-CWE-noinfo

Referencias

JSON original (NVD)

Mostrar

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  "id": "CVE-2026-31406",
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      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: Fix work re-schedule after cancel in xfrm_nat_keepalive_net_fini()\n\nAfter cancel_delayed_work_sync() is called from\nxfrm_nat_keepalive_net_fini(), xfrm_state_fini() flushes remaining\nstates via __xfrm_state_delete(), which calls\nxfrm_nat_keepalive_state_updated() to re-schedule nat_keepalive_work.\n\nThe following is a simple race scenario:\n\n           cpu0                             cpu1\n\ncleanup_net() [Round 1]\n  ops_undo_list()\n    xfrm_net_exit()\n      xfrm_nat_keepalive_net_fini()\n        cancel_delayed_work_sync(nat_keepalive_work);\n      xfrm_state_fini()\n        xfrm_state_flush()\n          xfrm_state_delete(x)\n            __xfrm_state_delete(x)\n              xfrm_nat_keepalive_state_updated(x)\n                schedule_delayed_work(nat_keepalive_work);\n  rcu_barrier();\n  net_complete_free();\n  net_passive_dec(net);\n    llist_add(&net->defer_free_list, &defer_free_list);\n\ncleanup_net() [Round 2]\n  rcu_barrier();\n  net_complete_free()\n    kmem_cache_free(net_cachep, net);\n                                     nat_keepalive_work()\n                                       // on freed net\n\nTo prevent this, cancel_delayed_work_sync() is replaced with\ndisable_delayed_work_sync()."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nxfrm: Corrige la reprogramación del trabajo después de la cancelación en xfrm_nat_keepalive_net_fini()\n\nDespués de que se llama a cancel_delayed_work_sync() desde xfrm_nat_keepalive_net_fini(), xfrm_state_fini() vacía los estados restantes a través de __xfrm_state_delete(), que llama a xfrm_nat_keepalive_state_updated() para reprogramar nat_keepalive_work.\n\nEl siguiente es un escenario de carrera simple:\n\n           cpu0                             cpu1\n\ncleanup_net() [Ronda 1]\n  ops_undo_list()\n    xfrm_net_exit()\n      xfrm_nat_keepalive_net_fini()\n        cancel_delayed_work_sync(nat_keepalive_work);\n      xfrm_state_fini()\n        xfrm_state_flush()\n          xfrm_state_delete(x)\n            __xfrm_state_delete(x)\n              xfrm_nat_keepalive_state_updated(x)\n                schedule_delayed_work(nat_keepalive_work);\n  rcu_barrier();\n  net_complete_free();\n  net_passive_dec(net);\n    llist_add(&net -> defer_free_list, &defer_free_list);\n\ncleanup_net() [Ronda 2]\n  rcu_barrier();\n  net_complete_free()\n    kmem_cache_free(net_cachep, net);\n                                     nat_keepalive_work()\n                                       // en net liberado\n\nPara evitar esto, cancel_delayed_work_sync() se reemplaza con disable_delayed_work_sync()."
    }
  ],
  "lastModified": "2026-07-24T22:10:00.140",
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