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CVE-2026-44452

Estado: AnalizadaMedia (5.9)—

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 8dc37cb, when h2o receives a ClientHello message over TLS or QUIC and it contains a zero-length SNI extension, the h2o server runs over the zero-length hostname while trying to copy the hostname, assuming that it is NULL-terminated. This is a potential denial-of-service attack vector in sense that it might trigger segmentation violation. This issue has been fixed by commit 8dc37cb.

CVSS

Probabilidad de explotación (EPSS)

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)

H2O — H2O

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-44452",
  "cveTags": [],
  "metrics": {
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          "id": "CVE-2026-44452",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
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            },
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              "technicalImpact": "partial"
            }
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          "version": "2.0.3",
          "timestamp": "2026-07-17T14:03:32.725590Z"
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          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 2.2
      }
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      "affectedData": [
        {
          "vendor": "h2o",
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          "versions": [
            {
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              "version": "< 8dc37cb"
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  "published": "2026-07-16T23:16:17.280",
  "references": [
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      "url": "https://github.com/h2o/h2o/commit/8dc37cb1e6171f7f772667618ea440696fed82c3",
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    }
  ],
  "lastModified": "2026-08-06T13:56:18.987",
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