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CVE-2018-0956

Status: ModifiedHigh (7.5)—

A denial of service vulnerability exists in the HTTP 2.0 protocol stack (HTTP.sys) when HTTP.sys improperly parses specially crafted HTTP 2.0 requests, aka "HTTP.sys Denial of Service 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-2018-0956",
  "cveTags": [],
  "metrics": {
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        "type": "Primary",
        "source": "nvd@nist.gov",
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          "baseScore": 7.8,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:C",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "COMPLETE",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 6.9,
        "baseSeverity": "HIGH",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
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    "cvssMetricV30": [
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          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
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  "affected": [
    {
      "source": "secure@microsoft.com",
      "affectedData": [
        {
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          "product": "Windows Server 2016",
          "versions": [
            {
              "status": "affected",
              "version": "(Server Core installation)"
            }
          ]
        },
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          "versions": [
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              "status": "affected",
              "version": "32-bit Systems"
            },
            {
              "status": "affected",
              "version": "Version 1511 for 32-bit Systems"
            },
            {
              "status": "affected",
              "version": "Version 1511 for x64-based Systems"
            },
            {
              "status": "affected",
              "version": "Version 1607 for 32-bit Systems"
            },
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              "status": "affected",
              "version": "Version 1607 for x64-based Systems"
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              "status": "affected",
              "version": "Version 1703 for 32-bit Systems"
            },
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              "status": "affected",
              "version": "Version 1703 for x64-based Systems"
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            {
              "status": "affected",
              "version": "Version 1709 for 32-bit Systems"
            },
            {
              "status": "affected",
              "version": "Version 1709 for x64-based Systems"
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              "status": "affected",
              "version": "x64-based Systems"
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          "product": "Windows 10 Servers",
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              "version": "version 1709  (Server Core Installation)"
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  ],
  "published": "2018-04-12T01:29:06.317",
  "references": [
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      "tags": [
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        "VDB Entry"
      ],
      "source": "secure@microsoft.com"
    },
    {
      "url": "http://www.securitytracker.com/id/1040661",
      "tags": [
        "Third Party Advisory",
        "VDB Entry"
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      "source": "secure@microsoft.com"
    },
    {
      "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-0956",
      "tags": [
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      "source": "secure@microsoft.com"
    },
    {
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      "tags": [
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    },
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      "tags": [
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        "VDB Entry"
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-0956",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
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      "source": "nvd@nist.gov",
      "description": [
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          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A denial of service vulnerability exists in the HTTP 2.0 protocol stack (HTTP.sys) when HTTP.sys improperly parses specially crafted HTTP 2.0 requests, aka \"HTTP.sys Denial of Service Vulnerability.\" This affects Windows Server 2016, Windows 10, Windows 10 Servers."
    },
    {
      "lang": "es",
      "value": "Existe una vulnerabilidad de denegación de servicio (DoS) en la pila del protocolo HTTP 2.0 (HTTP.sys) cuando este analiza incorrectamente peticiones HTTP 2.0 especialmente manipuladas. Esto también se conoce como \"HTTP.sys Denial of Service Vulnerability\". Esto afecta a Windows Server 2016, Windows 10 y Windows 10 Servers."
    }
  ],
  "lastModified": "2026-06-17T01:32:00.697",
  "configurations": [
    {
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          "negate": false,
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  "sourceIdentifier": "secure@microsoft.com"
}