{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "6.5.0"
              },
              {
                "fixed": "6.6.7"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "439a8f669c6788b512dd76011c4476830d67515b"
            },
            {
              "fixed": "1fa1f46cd420ac5b57bb4c04c959b58f3c79158c"
            }
          ],
          "repo": "https://github.com/socketio/socket.io",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-gr94-w7qr-f4j3"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-20"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59724.json"
  },
  "details": "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.",
  "id": "CVE-2026-59724",
  "modified": "2026-07-15T01:49:20.612839733Z",
  "published": "2026-07-08T15:35:39.813Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/socketio/socket.io/releases/tag/engine.io@6.6.7"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59724.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/socketio/socket.io/security/advisories/GHSA-gr94-w7qr-f4j3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-59724"
    },
    {
      "type": "FIX",
      "url": "https://github.com/socketio/socket.io/commit/1fa1f46cd420ac5b57bb4c04c959b58f3c79158c"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Socket.IO: Engine.IO WebTransport SID DoS"
}