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CVE-2018-8435

Status: ModifiedMedium (4.2)—

A security feature bypass vulnerability exists when Windows Hyper-V BIOS loader fails to provide a high-entropy source, aka "Windows Hyper-V Security Feature Bypass Vulnerability." This affects Windows Server 2016, Windows 10, Windows 10 Servers.

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).

Affected technologies (2)

Microsoft — Windows 10Microsoft — Windows Server 2016

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2018-8435",
  "cveTags": [],
  "metrics": {
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        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 2.3,
          "accessVector": "ADJACENT_NETWORK",
          "vectorString": "AV:A/AC:M/Au:S/C:N/I:P/A:N",
          "authentication": "SINGLE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "MEDIUM",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "LOW",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 4.4,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV30": [
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        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.0",
          "baseScore": 4.2,
          "attackVector": "ADJACENT_NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.0/AV:A/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "NONE",
          "privilegesRequired": "HIGH",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 0.5
      }
    ]
  },
  "affected": [
    {
      "source": "secure@microsoft.com",
      "affectedData": [
        {
          "vendor": "Microsoft",
          "product": "Windows Server 2016",
          "versions": [
            {
              "status": "affected",
              "version": "(Server Core installation)"
            }
          ]
        },
        {
          "vendor": "Microsoft",
          "product": "Windows 10",
          "versions": [
            {
              "status": "affected",
              "version": "Version 1607 for x64-based Systems"
            },
            {
              "status": "affected",
              "version": "Version 1703 for x64-based Systems"
            },
            {
              "status": "affected",
              "version": "Version 1709 for x64-based Systems"
            },
            {
              "status": "affected",
              "version": "Version 1803 for x64-based Systems"
            },
            {
              "status": "affected",
              "version": "x64-based Systems"
            }
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        },
        {
          "vendor": "Microsoft",
          "product": "Windows 10 Servers",
          "versions": [
            {
              "status": "affected",
              "version": "version 1709  (Server Core Installation)"
            },
            {
              "status": "affected",
              "version": "version 1803  (Server Core Installation)"
            }
          ]
        }
      ]
    }
  ],
  "published": "2018-09-13T00:29:03.757",
  "references": [
    {
      "url": "http://www.securityfocus.com/bid/105240",
      "tags": [
        "Third Party Advisory",
        "VDB Entry"
      ],
      "source": "secure@microsoft.com"
    },
    {
      "url": "http://www.securitytracker.com/id/1041624",
      "tags": [
        "Third Party Advisory",
        "VDB Entry"
      ],
      "source": "secure@microsoft.com"
    },
    {
      "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8435",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "source": "secure@microsoft.com"
    },
    {
      "url": "http://www.securityfocus.com/bid/105240",
      "tags": [
        "Third Party Advisory",
        "VDB Entry"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "http://www.securitytracker.com/id/1041624",
      "tags": [
        "Third Party Advisory",
        "VDB Entry"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8435",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-331"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A security feature bypass vulnerability exists when Windows Hyper-V BIOS loader fails to provide a high-entropy source, aka \"Windows Hyper-V Security Feature Bypass Vulnerability.\" This affects Windows Server 2016, Windows 10, Windows 10 Servers."
    },
    {
      "lang": "es",
      "value": "Existe una vulnerabilidad de omisión de la característica de seguridad cuando el cargador de BIOS de Windows Hyper-V no puede proporcionar una fuente con alta entropía. Esto también se conoce como \"Windows Hyper-V Security Feature Bypass Vulnerability\". Esto afecta a Windows Server 2016, Windows 10 y Windows 10 Servers."
    }
  ],
  "lastModified": "2026-06-17T02:04:52.017",
  "configurations": [
    {
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        {
          "negate": false,
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          "operator": "OR"
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  ],
  "sourceIdentifier": "secure@microsoft.com"
}