CVE-2016-4979

Estado: ModificadaAlta (7.5)—
The Apache HTTP Server 2.4.18 through 2.4.20, when mod_http2 and mod_ssl are enabled, does not properly recognize the "SSLVerifyClient require" directive for HTTP/2 request authorization, which allows remote attackers to bypass intended access restrictions by leveraging the ability to send multiple requests over a single connection and aborting a renegotiation.
CVSS

Versión: 3.0
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Puntuación base: 7.5
Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 19%
Percentil entre todas las CVEs puntuadas: 97
Fecha de la puntuación: 6/10/2026
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).
Tecnologías afectadas (1)

Apache — Http Server
CWE

CWE-284
Referencias

JSON original (NVD)

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{
  "id": "CVE-2016-4979",
  "cveTags": [],
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          "vectorString": "AV:N/AC:L/Au:N/C:N/I:P/A:N",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "LOW",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "NONE"
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        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
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          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
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  "vulnStatus": "Modified",
  "weaknesses": [
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      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-284"
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  "descriptions": [
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      "lang": "en",
      "value": "The Apache HTTP Server 2.4.18 through 2.4.20, when mod_http2 and mod_ssl are enabled, does not properly recognize the \"SSLVerifyClient require\" directive for HTTP/2 request authorization, which allows remote attackers to bypass intended access restrictions by leveraging the ability to send multiple requests over a single connection and aborting a renegotiation."
    },
    {
      "lang": "es",
      "value": "El servidor HTTP Apache 2.4.18 hasta la versión 2.4.20, cuando mod_http2 y mod_ssl están activados, no reconoce adecuadamente la directiva \"SSLVerifyClient require\" para autorización de petición HTTP/2, lo que permite a atacantes remotos eludir las restricciones destinadas al acceso aprovechando la capacidad de enviar múltiples peticiones sobre una sola conexión y abortar una renegociación."
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  "lastModified": "2026-06-17T00:48:33.000",
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