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CVE-2026-64898

Status: AnalyzedHigh (7.8)—

Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Vector AV:L + UI:R indica ejecución en cliente: abrir documento Office preparado provoca desbordamiento de búfer en heap que ejecuta código arbitrario localmente.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Restrict Web-Based ContentPrivileged Account ManagementLimit Software InstallationExecution PreventionBehavior Prevention on EndpointDisable or Remove Feature or Program

Affected technologies (5)

Microsoft — 365 AppsMicrosoft — Microsoft 365Microsoft — Office 2019Microsoft — Office 2021Microsoft — Office 2024

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-64898",
  "cveTags": [],
  "metrics": {
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          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-08-12T03:57:04.472018Z"
        }
      }
    ],
    "cvssMetricV31": [
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        "type": "Secondary",
        "source": "secure@microsoft.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "secure@microsoft.com",
      "affectedData": [
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          ],
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          "platforms": [
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          "versions": [
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          "platforms": [
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        {
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          "versions": [
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              "version": "16.0.1",
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        },
        {
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          "versions": [
            {
              "status": "affected",
              "version": "16.0.0",
              "lessThan": "16.112.26081010",
              "versionType": "custom"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-08-11T17:18:50.567",
  "references": [
    {
      "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64898",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "secure@microsoft.com"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "secure@microsoft.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-122"
        },
        {
          "lang": "en",
          "value": "CWE-190"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally."
    }
  ],
  "lastModified": "2026-08-13T18:57:11.080",
  "configurations": [
    {
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            },
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  "sourceIdentifier": "secure@microsoft.com"
}