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CVE-2026-74721

Estado: RecibidaAlta (7.8)—

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

accel/amxdna: Fix page-insertion errors in amdxdna_insert_pages()

Two error paths in amdxdna_insert_pages() called vma->vm_ops->close(vma) before returning an error code to the caller. This is incorrect: amdxdna_gem_obj_mmap() registers an HMM interval notifier before calling amdxdna_insert_pages(), and on a hard error it jumps to hmm_unreg to undo that registration.

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Calling vm_ops->close() manually — which drops the shmem pages_pin_count and the GEM object reference that backs the VMA — before the mmap syscall has even returned causes those resources to be released while the VMA is still alive. The kernel VMA teardown will call vm_ops->close() a second time when the process later unmaps the range, producing a reference count underflow.

Replace both hard-error returns with a deferred-fault approach that keeps the VMA alive and retries page insertion through the HMM range-fault path.

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) en kernel Linux que causa reference count underflow y corrupción de memoria, permitiendo escalada de privilegios o DoS. Acceso local con privilegios sin interacción.

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 ProgramRestrict File and Directory PermissionsRemote Data StorageFilter Network TrafficExecution PreventionEncrypt Sensitive Information

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-2026-74721",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "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": "e486147c912f653ef4b60a6c7dbd4168a4c56a9f",
              "lessThan": "1501e4d07c6fee0d50531a0d1cb2be01a63e6e75",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e486147c912f653ef4b60a6c7dbd4168a4c56a9f",
              "lessThan": "8d51e0fd3e698919d2adeff71936377f0c0d4aa0",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "drivers/accel/amdxdna/amdxdna_gem.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.16",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "drivers/accel/amdxdna/amdxdna_gem.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-22T16:16:47.080",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1501e4d07c6fee0d50531a0d1cb2be01a63e6e75",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8d51e0fd3e698919d2adeff71936377f0c0d4aa0",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\naccel/amxdna: Fix page-insertion errors in amdxdna_insert_pages()\n\nTwo error paths in amdxdna_insert_pages() called vma->vm_ops->close(vma)\nbefore returning an error code to the caller.  This is incorrect:\namdxdna_gem_obj_mmap() registers an HMM interval notifier before calling\namdxdna_insert_pages(), and on a hard error it jumps to hmm_unreg to undo\nthat registration.  Calling vm_ops->close() manually — which drops the\nshmem pages_pin_count and the GEM object reference that backs the VMA —\nbefore the mmap syscall has even returned causes those resources to be\nreleased while the VMA is still alive.  The kernel VMA teardown will call\nvm_ops->close() a second time when the process later unmaps the range,\nproducing a reference count underflow.\n\nReplace both hard-error returns with a deferred-fault approach that keeps\nthe VMA alive and retries page insertion through the HMM range-fault path."
    }
  ],
  "lastModified": "2026-08-25T06:18:57.913",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}