CVE-2026-23327

Estado: ModificadaAlta (7.1)—

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

cxl/mbox: validate payload size before accessing contents in cxl_payload_from_user_allowed()

cxl_payload_from_user_allowed() casts and dereferences the input payload without first verifying its size. When a raw mailbox command is sent with an undersized payload (ie: 1 byte for CXL_MBOX_OP_CLEAR_LOG, which expects a 16-byte UUID), uuid_equal() reads past the allocated buffer, triggering a KASAN splat:

Add 'in_size' parameter to cxl_payload_from_user_allowed() and validate the payload is large enough.

Detalles técnicos trazas, registros y código del informe original

BUG: KASAN: slab-out-of-bounds in memcmp+0x176/0x1d0 lib/string.c:683
Read of size 8 at addr ffff88810130f5c0 by task syz.1.62/2258

CPU: 2 UID: 0 PID: 2258 Comm: syz.1.62 Not tainted 6.19.0-dirty #3 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xab/0xe0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xce/0x650 mm/kasan/report.c:482
 kasan_report+0xce/0x100 mm/kasan/report.c:595
 memcmp+0x176/0x1d0 lib/string.c:683
 uuid_equal include/linux/uuid.h:73 [inline]
 cxl_payload_from_user_allowed drivers/cxl/core/mbox.c:345 [inline]
 cxl_mbox_cmd_ctor drivers/cxl/core/mbox.c:368 [inline]
 cxl_validate_cmd_from_user drivers/cxl/core/mbox.c:522 [inline]
 cxl_send_cmd+0x9c0/0xb50 drivers/cxl/core/mbox.c:643
 __cxl_memdev_ioctl drivers/cxl/core/memdev.c:698 [inline]
 cxl_memdev_ioctl+0x14f/0x190 drivers/cxl/core/memdev.c:713
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xa8/0x330 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdaf331ba79
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdaf1d77038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fdaf3585fa0 RCX: 00007fdaf331ba79
RDX: 00002000000001c0 RSI: 00000000c030ce02 RDI: 0000000000000003
RBP: 00007fdaf33749df R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdaf3586038 R14: 00007fdaf3585fa0 R15: 00007ffced2af768
 </TASK>

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: 0.12%
Percentil entre todas las CVEs puntuadas: 2
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 principalT1499.004 Application or System Exploitationimpact70 %

AV:L sin UI:R indica escalada local. El buffer overflow (CWE-125) causa Denial of Service al leer fuera de límites sin validación previa del tamaño del payload en ioctl.

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-125

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-23327",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.1,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.2,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6179045ccc0c6229dc449afc1701dc7fbd40571f",
              "lessThan": "dc184ac2f0ba77ae19725ee06ad3ab36bb9d1f61",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6179045ccc0c6229dc449afc1701dc7fbd40571f",
              "lessThan": "7c8a7b7f063b7e7ae9bba4cbaa14a5d2fe3a55e1",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6179045ccc0c6229dc449afc1701dc7fbd40571f",
              "lessThan": "60b5d1f68338aff2c5af0113f04aefa7169c50c2",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/cxl/core/mbox.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.19"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "5.19",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "6.19.7",
              "versionType": "semver",
              "lessThanOrEqual": "6.19.*"
            },
            {
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/cxl/core/mbox.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-03-25T11:16:29.837",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/60b5d1f68338aff2c5af0113f04aefa7169c50c2",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7c8a7b7f063b7e7ae9bba4cbaa14a5d2fe3a55e1",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/dc184ac2f0ba77ae19725ee06ad3ab36bb9d1f61",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncxl/mbox: validate payload size before accessing contents in cxl_payload_from_user_allowed()\n\ncxl_payload_from_user_allowed() casts and dereferences the input\npayload without first verifying its size. When a raw mailbox command\nis sent with an undersized payload (ie: 1 byte for CXL_MBOX_OP_CLEAR_LOG,\nwhich expects a 16-byte UUID), uuid_equal() reads past the allocated buffer,\ntriggering a KASAN splat:\n\nBUG: KASAN: slab-out-of-bounds in memcmp+0x176/0x1d0 lib/string.c:683\nRead of size 8 at addr ffff88810130f5c0 by task syz.1.62/2258\n\nCPU: 2 UID: 0 PID: 2258 Comm: syz.1.62 Not tainted 6.19.0-dirty #3 PREEMPT(voluntary)\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014\nCall Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0xab/0xe0 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0xce/0x650 mm/kasan/report.c:482\n kasan_report+0xce/0x100 mm/kasan/report.c:595\n memcmp+0x176/0x1d0 lib/string.c:683\n uuid_equal include/linux/uuid.h:73 [inline]\n cxl_payload_from_user_allowed drivers/cxl/core/mbox.c:345 [inline]\n cxl_mbox_cmd_ctor drivers/cxl/core/mbox.c:368 [inline]\n cxl_validate_cmd_from_user drivers/cxl/core/mbox.c:522 [inline]\n cxl_send_cmd+0x9c0/0xb50 drivers/cxl/core/mbox.c:643\n __cxl_memdev_ioctl drivers/cxl/core/memdev.c:698 [inline]\n cxl_memdev_ioctl+0x14f/0x190 drivers/cxl/core/memdev.c:713\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:597 [inline]\n __se_sys_ioctl fs/ioctl.c:583 [inline]\n __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xa8/0x330 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7fdaf331ba79\nCode: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007fdaf1d77038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\nRAX: ffffffffffffffda RBX: 00007fdaf3585fa0 RCX: 00007fdaf331ba79\nRDX: 00002000000001c0 RSI: 00000000c030ce02 RDI: 0000000000000003\nRBP: 00007fdaf33749df R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000\nR13: 00007fdaf3586038 R14: 00007fdaf3585fa0 R15: 00007ffced2af768\n </TASK>\n\nAdd 'in_size' parameter to cxl_payload_from_user_allowed() and validate\nthe payload is large enough."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ncxl/mbox: validar el tamaño de la carga útil antes de acceder a los contenidos en cxl_payload_from_user_allowed()\n\ncxl_payload_from_user_allowed() convierte y desreferencia la carga útil de entrada sin verificar primero su tamaño. Cuando se envía un comando de buzón sin procesar con una carga útil de tamaño insuficiente (es decir: 1 byte para CXL_MBOX_OP_CLEAR_LOG, que espera un UUID de 16 bytes), uuid_equal() lee más allá del búfer asignado, lo que activa un KASAN splat:\n\nBUG: KASAN: slab-out-of-bounds en memcmp+0x176/0x1d0 lib/string.c:683\nLectura de tamaño 8 en la dirección ffff88810130f5c0 por la tarea syz.1.62/2258\n\nCPU: 2 UID: 0 PID: 2258 Comm: syz.1.62 No contaminado 6.19.0-dirty #3 PREEMPT(voluntary)\nNombre del hardware: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014\nTraza de llamadas:\n \n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0xab/0xe0 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0xce/0x650 mm/kasan/report.c:482\n kasan_report+0xce/0x100 mm/kasan/report.c:595\n memcmp+0x176/0x1d0 lib/string.c:683\n uuid_equal include/linux/uuid.h:73 [inline]\n cxl_payload_from_user_allowed drivers/cxl/core/mbox.c:345 [inline]\n cxl_mbox_cmd_ctor drivers/cxl/core/mbox.c:368 [inline]\n cxl_validate_cmd_from_user drivers/cxl/core/mbox.c:522 [inline]\n cxl_send_cmd+0x9c0/0xb50 drivers/cxl/core/mbox.c:643\n __cxl_memdev_ioctl drivers/cxl/core/memdev.c:698 [inline]\n cxl_memdev_ioctl+0x14f/0x190 drivers/cxl/core/memdev.c:713\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:597 [inline]\n __se_sys_ioctl fs/ioctl.c:583 [inline]\n __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xa8/0x330 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7fdaf331ba79\nCode: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 &lt;48&gt; 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007fdaf1d77038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\nRAX: ffffffffffffffda RBX: 00007fdaf3585fa0 RCX: 00007fdaf331ba79\nRDX: 00002000000001c0 RSI: 00000000c030ce02 RDI: 0000000000000003\nRBP: 00007fdaf33749df R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000\nR13: 00007fdaf3586038 R14: 00007fdaf3585fa0 R15: 00007ffced2af768\n \n\nAñadir el parámetro 'in_size' a cxl_payload_from_user_allowed() y validar que la carga útil sea lo suficientemente grande."
    }
  ],
  "lastModified": "2026-06-17T10:21:20.130",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "74C0D01A-385D-4859-8FCC-93ACC7B4B847",
              "versionEndExcluding": "6.19.7",
              "versionStartIncluding": "5.19.1"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:5.19:-:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "9D759CCF-9E1B-41B2-81AA-CB580C5F3EEC"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"
            },
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              "vulnerable": true,
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            },
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              "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"
            },
            {
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              "vulnerable": true,
              "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "512EE3A8-A590-4501-9A94-5D4B268D6138"
            }
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          "operator": "OR"
        }
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  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}