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CVE-2026-74520

Estado: RecibidaAlta (8.8)—

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

iommu/iommufd: Fix IOPF group ownership UAF

iopf_group_alloc() links each last-page IOPF group into the generic IOPF pending list before invoking the domain fault handler. iommufd_fault_iopf_handler() also queued an accepted group in the IOMMUFD deliver list without removing it from the generic pending list.

When detach or HWPT replacement drops the device's IOPF reference count to zero, an IOMMU driver may call iopf_queue_remove_device(). That function responds to and frees groups through the generic pending list without removing the same groups from IOMMUFD's deliver list or response xarray. A later read, response, or cleanup can then access the freed group and cause a UAF.

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Fix this by dequeuing an accepted group from the generic pending list before IOMMUFD queues it for userspace response. Make iopf_group_response() send a response regardless of pending-list membership, so the dequeued group can still be completed by IOMMUFD.

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.

Vulnerabilidad local (AV:L/PR:L) sin interacción de usuario que causa UAF en el kernel; permite escalar privilegios (S:C, I:H) o denegar servicio mediante acceso a memoria liberada.

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 ProgramFilter Network TrafficExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate Software

Tecnologías afectadas (1)

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

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-74520",
  "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"
        },
        "impactScore": 6,
        "exploitabilityScore": 2
      }
    ]
  },
  "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": "34765cbc679c59ea5d952d738d2d16bf4aadc497",
              "lessThan": "6da8f37419dd4c456f26fc203f04e000186f4b3d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "34765cbc679c59ea5d952d738d2d16bf4aadc497",
              "lessThan": "4e74a369236424114b94cf6a9f5ff9e848b430b4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "34765cbc679c59ea5d952d738d2d16bf4aadc497",
              "lessThan": "738e6f32e61d80b554e37015ecb7bc620b88001c",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/iommu/io-pgfault.c",
            "drivers/iommu/iommufd/eventq.c",
            "include/linux/iommu.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.11",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/iommu/io-pgfault.c",
            "drivers/iommu/iommufd/eventq.c",
            "include/linux/iommu.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T13:17:57.210",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/4e74a369236424114b94cf6a9f5ff9e848b430b4",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6da8f37419dd4c456f26fc203f04e000186f4b3d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/738e6f32e61d80b554e37015ecb7bc620b88001c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/iommufd: Fix IOPF group ownership UAF\n\niopf_group_alloc() links each last-page IOPF group into the generic IOPF\npending list before invoking the domain fault handler.\niommufd_fault_iopf_handler() also queued an accepted group in the\nIOMMUFD deliver list without removing it from the generic pending list.\n\nWhen detach or HWPT replacement drops the device's IOPF reference count\nto zero, an IOMMU driver may call iopf_queue_remove_device(). That\nfunction responds to and frees groups through the generic pending list\nwithout removing the same groups from IOMMUFD's deliver list or response\nxarray. A later read, response, or cleanup can then access the freed\ngroup and cause a UAF.\n\nFix this by dequeuing an accepted group from the generic pending list\nbefore IOMMUFD queues it for userspace response.\nMake iopf_group_response() send a response regardless of pending-list\nmembership, so the dequeued group can still be completed by IOMMUFD."
    }
  ],
  "lastModified": "2026-08-17T06:19:48.827",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}