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CVE-2026-19773

Estado: Pendiente de análisisCrítica (9.8)—

libwebsockets HTTP/2 HPACK Path Header Parsing Out-Of-Bounds Write Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of libwebsockets. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the parsing of HTTP/2 HPACK path header. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-31036.

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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vector CVSS AV:N/PR:N/UI:N indica acceso de red sin autenticación. CWE-787 (buffer overflow) en parsing de cabeceras HTTP/2 permite RCE remoto. Ejecución de código arbitraria confirmada en descripción.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Privileged Account ManagementVulnerability ScanningRestrict Web-Based ContentNetwork SegmentationLimit Software InstallationLimit Access to Resource Over Network

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Libwebsockets — LibwebsocketsAI

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-19773",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-19773",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-09-15T00:00:00+00:00"
        }
      }
    ],
    "cvssMetricV30": [
      {
        "type": "Secondary",
        "source": "zdi-disclosures@trendmicro.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.0",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "zdi-disclosures@trendmicro.com",
      "affectedData": [
        {
          "vendor": "libwebsockets",
          "product": "libwebsockets",
          "versions": [
            {
              "status": "affected",
              "version": "b4b5aed3903eaff09cd76a410f69bbe5dff66f8e"
            }
          ],
          "defaultStatus": "unknown"
        }
      ]
    }
  ],
  "published": "2026-09-15T19:17:17.747",
  "references": [
    {
      "url": "https://github.com/warmcat/libwebsockets/commit/824151862f37bc72f46d9a3e01d5b9408d313a0b",
      "source": "zdi-disclosures@trendmicro.com"
    },
    {
      "url": "https://www.zerodayinitiative.com/advisories/ZDI-26-590/",
      "source": "zdi-disclosures@trendmicro.com"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "zdi-disclosures@trendmicro.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "libwebsockets HTTP/2 HPACK Path Header Parsing Out-Of-Bounds Write Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of libwebsockets. Authentication is not required to exploit this vulnerability.\n\nThe specific flaw exists within the parsing of HTTP/2 HPACK path header. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-31036."
    }
  ],
  "lastModified": "2026-09-18T19:10:46.443",
  "sourceIdentifier": "zdi-disclosures@trendmicro.com"
}