CVE-2026-74580

Estado: RecibidaAlta (8.8)—

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

vhost: reset the vring metadata cache on vring reconfiguration

vq->meta_iotlb[] caches the vhost_iotlb_map that backs each vring metadata region, and iotlb_access_ok() returns early on a cache hit, taking the hit as proof that the region has already been validated:

The cache is reset on VHOST_IOTLB_UPDATE and VHOST_IOTLB_INVALIDATE, on device IOTLB (re)initialisation and on vq reset, but not when VHOST_SET_VRING_ADDR replaces vq->desc, vq->avail and vq->used, nor when VHOST_SET_VRING_NUM changes the region sizes.

With a device IOTLB attached both ioctls are accepted while the vq is live, and neither validates the addresses at ioctl time: vq_access_ok() and vq_log_used_access_ok() return true early because the addresses are GIOVAs, deferring validation to prefetch time.

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Once the cache has been populated that deferred validation no longer runs -- vq_meta_prefetch() hits the stale entry and returns true -- and vhost_vq_meta_fetch() keeps translating through the old mapping as

for an address the mapping no longer covers. vhost_copy_to_user() and vhost_copy_from_user() consume the result with __copy_to_user() and __copy_from_user(), which do not check it either, so a subsequent used ring update or descriptor fetch accesses memory outside the region the IOTLB actually maps.

Reset the metadata cache whenever the vring is reconfigured, so the new addresses are pushed back through iotlb_access_ok()'s slow path.

Detalles técnicos trazas, registros y código del informe original

	if (vhost_vq_meta_fetch(vq, addr, len, type))
		return true;

	map->addr + addr - map->start

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Puntuación base: 8.8

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 principalT1005 Data from Local Systemcollection80 %
Impacto secundarioT1059 Command and Scripting Interpreterexecution70 %
Impacto secundarioT1565 Data Manipulationimpact75 %

Escalada de privilegios local sin interacción (AV:L, PR:L, UI:N). El atacante con privilegios locales explota un fallo de validación de direcciones en la caché vring IOTLB para acceder a memoria fuera de los límites mapeados, permitiendo lectura/escritura de datos y ejecución de código con privilegi

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 Restrict File and Directory Permissions Privileged Account Management Remote Data Storage

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-74580",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 8.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
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  "published": "2026-08-21T17:16:44.210",
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvhost: reset the vring metadata cache on vring reconfiguration\n\nvq->meta_iotlb[] caches the vhost_iotlb_map that backs each vring\nmetadata region, and iotlb_access_ok() returns early on a cache hit,\ntaking the hit as proof that the region has already been validated:\n\n\tif (vhost_vq_meta_fetch(vq, addr, len, type))\n\t\treturn true;\n\nThe cache is reset on VHOST_IOTLB_UPDATE and VHOST_IOTLB_INVALIDATE, on\ndevice IOTLB (re)initialisation and on vq reset, but not when\nVHOST_SET_VRING_ADDR replaces vq->desc, vq->avail and vq->used, nor when\nVHOST_SET_VRING_NUM changes the region sizes.\n\nWith a device IOTLB attached both ioctls are accepted while the vq is\nlive, and neither validates the addresses at ioctl time: vq_access_ok()\nand vq_log_used_access_ok() return true early because the addresses are\nGIOVAs, deferring validation to prefetch time.  Once the cache has been\npopulated that deferred validation no longer runs -- vq_meta_prefetch()\nhits the stale entry and returns true -- and vhost_vq_meta_fetch() keeps\ntranslating through the old mapping as\n\n\tmap->addr + addr - map->start\n\nfor an address the mapping no longer covers.  vhost_copy_to_user() and\nvhost_copy_from_user() consume the result with __copy_to_user() and\n__copy_from_user(), which do not check it either, so a subsequent used\nring update or descriptor fetch accesses memory outside the region the\nIOTLB actually maps.\n\nReset the metadata cache whenever the vring is reconfigured, so the new\naddresses are pushed back through iotlb_access_ok()'s slow path."
    }
  ],
  "lastModified": "2026-08-25T06:18:30.997",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}