CVE-2024-56664

Estado: ModificadaAlta (7)—

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

bpf, sockmap: Fix race between element replace and close()

Element replace (with a socket different from the one stored) may race with socket's close() link popping & unlinking. __sock_map_delete() unconditionally unrefs the (wrong) element:

// set map[0] = s0 map_update_elem(map, 0, s0)

Then close(map) enqueues bpf_map_free_deferred, which finally calls sock_map_free(). This results in some refcount_t warnings along with a KASAN splat [1].

Fix __sock_map_delete(), do not allow sock_map_unref() on elements that may have been replaced.

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The bu ---truncated---

Detalles técnicos trazas, registros y código del informe original

// drop fd of s0
close(s0)
  sock_map_close()
    lock_sock(sk)               (s0!)
    sock_map_remove_links(sk)
      link = sk_psock_link_pop()
      sock_map_unlink(sk, link)
        sock_map_delete_from_link
                                        // replace map[0] with s1
                                        map_update_elem(map, 0, s1)
                                          sock_map_update_elem
                                (s1!)       lock_sock(sk)
                                            sock_map_update_common
                                              psock = sk_psock(sk)
                                              spin_lock(&stab->lock)
                                              osk = stab->sks[idx]
                                              sock_map_add_link(..., &stab->sks[idx])
                                              sock_map_unref(osk, &stab->sks[idx])
                                                psock = sk_psock(osk)
                                                sk_psock_put(sk, psock)
                                                  if (refcount_dec_and_test(&psock))
                                                    sk_psock_drop(sk, psock)
                                              spin_unlock(&stab->lock)
                                            unlock_sock(sk)
          __sock_map_delete
            spin_lock(&stab->lock)
            sk = *psk                        // s1 replaced s0; sk == s1
            if (!sk_test || sk_test == sk)   // sk_test (s0) != sk (s1); no branch
              sk = xchg(psk, NULL)
            if (sk)
              sock_map_unref(sk, psk)        // unref s1; sks[idx] will dangle
                psock = sk_psock(sk)
                sk_psock_put(sk, psock)
                  if (refcount_dec_and_test())
                    sk_psock_drop(sk, psock)
            spin_unlock(&stab->lock)
    release_sock(sk)

[1]:
BUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330
Write of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063

CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
 <TASK>
 dump_stack_lvl+0x68/0x90
 print_report+0x174/0x4f6
 kasan_report+0xb9/0x190
 kasan_check_range+0x10f/0x1e0
 sock_map_free+0x10e/0x330
 bpf_map_free_deferred+0x173/0x320
 process_one_work+0x846/0x1420
 worker_thread+0x5b3/0xf80
 kthread+0x29e/0x360
 ret_from_fork+0x2d/0x70
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 1202:
 kasan_save_stack+0x1e/0x40
 kasan_save_track+0x10/0x30
 __kasan_slab_alloc+0x85/0x90
 kmem_cache_alloc_noprof+0x131/0x450
 sk_prot_alloc+0x5b/0x220
 sk_alloc+0x2c/0x870
 unix_create1+0x88/0x8a0
 unix_create+0xc5/0x180
 __sock_create+0x241/0x650
 __sys_socketpair+0x1ce/0x420
 __x64_sys_socketpair+0x92/0x100
 do_syscall_64+0x93/0x180
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Freed by task 46:
 kasan_save_stack+0x1e/0x40
 kasan_save_track+0x10/0x30
 kasan_save_free_info+0x37/0x60
 __kasan_slab_free+0x4b/0x70
 kmem_cache_free+0x1a1/0x590
 __sk_destruct+0x388/0x5a0
 sk_psock_destroy+0x73e/0xa50
 process_one_work+0x846/0x1420
 worker_thread+0x5b3/0xf80
 kthread+0x29e/0x360
 ret_from_fork+0x2d/0x70
 ret_from_fork_asm+0x1a/0x30

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7

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.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation75 %
Impacto secundarioT1059 Command and Scripting Interpreterexecution60 %

Vulnerabilidad local de race condition (CWE-362, CWE-416) en el kernel Linux con acceso local y privilegios limitados (PR:L). Permite escalada de privilegios mediante explotación de condiciones de carrera en sockmap, confirmado por KASAN splat y crash de kernel.

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 Prevention Threat Intelligence Program Restrict Web-Based Content Privileged Account Management Limit Software Installation Behavior Prevention on Endpoint

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-362, CWE-416

Referencias

JSON original (NVD)

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{
  "id": "CVE-2024-56664",
  "cveTags": [],
  "metrics": {
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        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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            {
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              "version": "6.1.125",
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              "lessThanOrEqual": "*"
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            "net/core/sock_map.c"
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  "published": "2024-12-27T15:15:26.297",
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        "Patch"
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    },
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  ],
  "vulnStatus": "Modified",
  "weaknesses": [
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      "source": "nvd@nist.gov",
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          "value": "CWE-416"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Fix race between element replace and close()\n\nElement replace (with a socket different from the one stored) may race\nwith socket's close() link popping & unlinking. __sock_map_delete()\nunconditionally unrefs the (wrong) element:\n\n// set map[0] = s0\nmap_update_elem(map, 0, s0)\n\n// drop fd of s0\nclose(s0)\n  sock_map_close()\n    lock_sock(sk)               (s0!)\n    sock_map_remove_links(sk)\n      link = sk_psock_link_pop()\n      sock_map_unlink(sk, link)\n        sock_map_delete_from_link\n                                        // replace map[0] with s1\n                                        map_update_elem(map, 0, s1)\n                                          sock_map_update_elem\n                                (s1!)       lock_sock(sk)\n                                            sock_map_update_common\n                                              psock = sk_psock(sk)\n                                              spin_lock(&stab->lock)\n                                              osk = stab->sks[idx]\n                                              sock_map_add_link(..., &stab->sks[idx])\n                                              sock_map_unref(osk, &stab->sks[idx])\n                                                psock = sk_psock(osk)\n                                                sk_psock_put(sk, psock)\n                                                  if (refcount_dec_and_test(&psock))\n                                                    sk_psock_drop(sk, psock)\n                                              spin_unlock(&stab->lock)\n                                            unlock_sock(sk)\n          __sock_map_delete\n            spin_lock(&stab->lock)\n            sk = *psk                        // s1 replaced s0; sk == s1\n            if (!sk_test || sk_test == sk)   // sk_test (s0) != sk (s1); no branch\n              sk = xchg(psk, NULL)\n            if (sk)\n              sock_map_unref(sk, psk)        // unref s1; sks[idx] will dangle\n                psock = sk_psock(sk)\n                sk_psock_put(sk, psock)\n                  if (refcount_dec_and_test())\n                    sk_psock_drop(sk, psock)\n            spin_unlock(&stab->lock)\n    release_sock(sk)\n\nThen close(map) enqueues bpf_map_free_deferred, which finally calls\nsock_map_free(). This results in some refcount_t warnings along with\na KASAN splat [1].\n\nFix __sock_map_delete(), do not allow sock_map_unref() on elements that\nmay have been replaced.\n\n[1]:\nBUG: KASAN: slab-use-after-free in sock_map_free+0x10e/0x330\nWrite of size 4 at addr ffff88811f5b9100 by task kworker/u64:12/1063\n\nCPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 Not tainted 6.12.0+ #125\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014\nWorkqueue: events_unbound bpf_map_free_deferred\nCall Trace:\n <TASK>\n dump_stack_lvl+0x68/0x90\n print_report+0x174/0x4f6\n kasan_report+0xb9/0x190\n kasan_check_range+0x10f/0x1e0\n sock_map_free+0x10e/0x330\n bpf_map_free_deferred+0x173/0x320\n process_one_work+0x846/0x1420\n worker_thread+0x5b3/0xf80\n kthread+0x29e/0x360\n ret_from_fork+0x2d/0x70\n ret_from_fork_asm+0x1a/0x30\n </TASK>\n\nAllocated by task 1202:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n __kasan_slab_alloc+0x85/0x90\n kmem_cache_alloc_noprof+0x131/0x450\n sk_prot_alloc+0x5b/0x220\n sk_alloc+0x2c/0x870\n unix_create1+0x88/0x8a0\n unix_create+0xc5/0x180\n __sock_create+0x241/0x650\n __sys_socketpair+0x1ce/0x420\n __x64_sys_socketpair+0x92/0x100\n do_syscall_64+0x93/0x180\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nFreed by task 46:\n kasan_save_stack+0x1e/0x40\n kasan_save_track+0x10/0x30\n kasan_save_free_info+0x37/0x60\n __kasan_slab_free+0x4b/0x70\n kmem_cache_free+0x1a1/0x590\n __sk_destruct+0x388/0x5a0\n sk_psock_destroy+0x73e/0xa50\n process_one_work+0x846/0x1420\n worker_thread+0x5b3/0xf80\n kthread+0x29e/0x360\n ret_from_fork+0x2d/0x70\n ret_from_fork_asm+0x1a/0x30\n\nThe bu\n---truncated---"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bpf, sockmap: Se corrige la competencia entre el reemplazo de elementos y close(). El reemplazo de elementos (con un socket diferente del almacenado) puede competir con el enlace de close() del socket, haciendo estallar y desvinculando el enlace. __sock_map_delete() anula la referencia incondicional del elemento (incorrecto): // establece map[0] = s0 map_update_elem(map, 0, s0) // elimina fd de s0 close(s0) sock_map_close() lock_sock(sk) (s0!) sock_map_remove_links(sk) link = sk_psock_link_pop() sock_map_unlink(sk, link) sock_map_delete_from_link // reemplaza map[0] con s1 map_update_elem(map, 0, s1) sock_map_update_elem (s1!) lock_sock(sk) sock_map_update_common psock = sk_psock(sk) spin_lock(&amp;stab-&gt;lock) osk = stab-&gt;sks[idx] sock_map_add_link(..., &amp;stab-&gt;sks[idx]) sock_map_unref(osk, &amp;stab-&gt;sks[idx]) psock = sk_psock(osk) sk_psock_put(sk, psock) si (conteo_de_referencias_y_pruebas(&amp;psock)) sk_psock_drop(sk, psock) desbloqueo_spin(&amp;stab-&gt;bloqueo) desbloqueo_sock(sk) __sock_map_delete bloqueo_spin(&amp;stab-&gt;bloqueo) sk = *psk // s1 reemplazó a s0; sk == s1 si (!sk_prueba || sk_prueba == sk) // sk_prueba (s0) != sk (s1); sin rama sk = xchg(psk, NULL) si (sk) sock_map_unref(sk, psk) // desreferenciar s1; sks[idx] dejará colgado psock = sk_psock(sk) sk_psock_put(sk, psock) if (refcount_dec_and_test()) sk_psock_drop(sk, psock) spin_unlock(&amp;stab-&gt;lock) release_sock(sk) Luego close(map) pone en cola bpf_map_free_deferred, que finalmente llama a sock_map_free(). Esto da como resultado algunas advertencias refcount_t junto con un splat KASAN [1]. Corrija __sock_map_delete(), no permita sock_map_unref() en elementos que pueden haber sido reemplazados. [1]: ERROR: KASAN: slab-use-after-free en sock_map_free+0x10e/0x330 Escritura de tamaño 4 en la dirección ffff88811f5b9100 por la tarea kworker/u64:12/1063 CPU: 14 UID: 0 PID: 1063 Comm: kworker/u64:12 No contaminado 6.12.0+ #125 Nombre del hardware: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 Cola de trabajo: events_unbound bpf_map_free_deferred Rastreo de llamadas:  dump_stack_lvl+0x68/0x90 print_report+0x174/0x4f6 Asignado por la tarea 1202: pila de guardado kasan+0x1e/0x40 seguimiento de guardado kasan+0x10/0x30 __kasan_slab_alloc+0x85/0x90 kmem_cache_alloc_noprof+0x131/0x450 sk_prot_alloc+0x5b/0x220 sk_alloc+0x2c/0x870 unix_create1+0x88/0x8a0 unix_create+0xc5/0x180 __sock_create+0x241/0x650 __sys_socketpair+0x1ce/0x420 __x64_sys_socketpair+0x92/0x100 do_syscall_64+0x93/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e Liberado por la tarea 46: kasan_save_stack+0x1e/0x40 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x60 __kasan_slab_free+0x4b/0x70 kmem_cache_free+0x1a1/0x590 __sk_destruct+0x388/0x5a0 sk_psock_destroy+0x73e/0xa50 process_one_work+0x846/0x1420 worker_thread+0x5b3/0xf80 kthread+0x29e/0x360 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x1a/0x30 La librería ---truncada---"
    }
  ],
  "lastModified": "2026-08-04T11:22:20.143",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "54ED2956-6164-49A7-8D04-741D1A16289C",
              "versionEndExcluding": "6.6.67",
              "versionStartIncluding": "4.20"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "0CB1A9BB-F95E-43DD-A2FD-147912FD91E5",
              "versionEndExcluding": "6.12.6",
              "versionStartIncluding": "6.7"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.13:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "62567B3C-6CEE-46D0-BC2E-B3717FBF7D13"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.13:rc2:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "5A073481-106D-4B15-B4C7-FB0213B8E1D4"
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          "operator": "OR"
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}