CVE-2009-2511

Status: ModifiedHigh (7.5)—💥 Exploit

Integer overflow in the CryptoAPI component in Microsoft Windows 2000 SP4, Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista Gold, SP1, and SP2, Windows Server 2008 Gold, SP2, and R2, and Windows 7 allows man-in-the-middle attackers to spoof arbitrary SSL servers and other entities via an X.509 certificate that has a malformed ASN.1 Object Identifier (OID) and was issued by a legitimate Certification Authority, aka "Integer Overflow in X.509 Object Identifiers Vulnerability."

CVSS

Version: 2.0
Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P
Base score: 7.5

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 13%
Percentile among all scored CVEs: 96
Score date: 10/7/2026

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).

💥 Public exploits

Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.

Published on Exploit-DB · Microsoft Internet Explorer 8 - X.509 Certificate Common Name Encoding Multiple Security Bypass Vulnerabilities (8/5/2009)

Affected technologies (6)

Microsoft — Windows 2000 Microsoft — Windows 7 Microsoft — Windows Server 2003 Microsoft — Windows Server 2008 Microsoft — Windows Vista Microsoft — Windows XP

CWEs

CWE-189

References

Raw JSON (NVD)

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{
  "id": "CVE-2009-2511",
  "cveTags": [],
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          "baseScore": 7.5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "LOW",
          "availabilityImpact": "PARTIAL",
          "confidentialityImpact": "PARTIAL"
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        "acInsufInfo": false,
        "impactScore": 6.4,
        "baseSeverity": "HIGH",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
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        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
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      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2009-10-14T10:30:01.517",
  "references": [
    {
      "url": "http://www.us-cert.gov/cas/techalerts/TA09-286A.html",
      "tags": [
        "US Government Resource"
      ],
      "source": "secure@microsoft.com"
    },
    {
      "url": "https://docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-056",
      "source": "secure@microsoft.com"
    },
    {
      "url": "https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6186",
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    },
    {
      "url": "http://www.us-cert.gov/cas/techalerts/TA09-286A.html",
      "tags": [
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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  "vulnStatus": "Modified",
  "weaknesses": [
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      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-189"
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  ],
  "descriptions": [
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      "lang": "en",
      "value": "Integer overflow in the CryptoAPI component in Microsoft Windows 2000 SP4, Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista Gold, SP1, and SP2, Windows Server 2008 Gold, SP2, and R2, and Windows 7 allows man-in-the-middle attackers to spoof arbitrary SSL servers and other entities via an X.509 certificate that has a malformed ASN.1 Object Identifier (OID) and was issued by a legitimate Certification Authority, aka \"Integer Overflow in X.509 Object Identifiers Vulnerability.\""
    },
    {
      "lang": "es",
      "value": "Desbordamiento de entero en el componente CryptoAPI en Microsoft Windows 2000 SP4, Windows XP SP2 y SP3, Windows Server 2003 SP2, Windows Vista Gold, SP1, y SP2, Windows Server 2008 Gold, SP2, y R2, y Windows 7 permite a atacantes man-in-the-middle engañar de forma arbitraria a servidores SSL y otras entidades a traves de un certificado X.509 que tiene un identificador de objeto (OID) malformado que fue creado por una certificadora legitima, también conocido como \"Vulnerabilidad de desbordamiento de entero en identificadores de objeto X.509\"."
    }
  ],
  "lastModified": "2026-06-16T23:09:36.713",
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}