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CVE-2026-59724

Full vulnerability record from the local CVENow database.

Description

Socket.IO enables bidirectional and low-latency communication for every platform. From 6.5.0 before 6.6.7, Engine.IO servers with WebTransport enabled can resolve a crafted session ID such as __proto__ through an inherited property of the clients object during WebTransport upgrade handling, causing a TypeError and denial of service. This issue is fixed in version 6.6.7.

Severity
HIGH
CVSS score
7.5 (v3.1)
Vulnerability status
Analyzed
Source identifier
Published
2026-07-08 16:16:32.980000
Last modified
2026-10-25 20:10:00.147000
View original CVE JSON
{
  "id": "CVE-2026-59724",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-08T16:16:32.980",
  "lastModified": "2026-10-25T20:10:00.147",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Socket.IO enables bidirectional and low-latency communication for every platform. From 6.5.0 before 6.6.7, Engine.IO servers with WebTransport enabled can resolve a crafted session ID such as __proto__ through an inherited property of the clients object during WebTransport upgrade handling, causing a TypeError and denial of service. This issue is fixed in version 6.6.7."
    },
    {
      "lang": "es",
      "value": "Socket.IO permite la comunicación bidireccional y de baja latencia para todas las plataformas. Desde la versión 6.5.0 hasta la 6.6.7, los servidores de Engine.IO con WebTransport habilitado pueden resolver un ID de sesión manipulado, como __proto__, a través de una propiedad heredada del objeto clients durante el manejo de la actualización de WebTransport, causando un TypeError y denegación de servicio. Este problema se corrige en la versión 6.6.7."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "socketio",
          "product": "socket.io",
          "versions": [
            {
              "version": ">= 6.5.0, < 6.6.7",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-08T17:58:43.578991Z",
          "id": "CVE-2026-59724",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-20"
        }
      ]
    },
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:socket:engine.io:*:*:*:*:*:node.js:*:*",
              "versionStartIncluding": "6.5.0",
              "versionEndExcluding": "6.6.7",
              "matchCriteriaId": "96612FDE-E815-461C-9ABA-08B2979A8698"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/socketio/socket.io/commit/1fa1f46cd420ac5b57bb4c04c959b58f3c79158c",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/socketio/socket.io/releases/tag/[email protected]",
      "source": "[email protected]",
      "tags": [
        "Release Notes"
      ]
    },
    {
      "url": "https://github.com/socketio/socket.io/security/advisories/GHSA-gr94-w7qr-f4j3",
      "source": "[email protected]",
      "tags": [
        "Patch",
        "Vendor Advisory",
        "Mitigation"
      ]
    }
  ]
}