Security advisory

{
  "id": "cfc197b6fda6bb583d161e7cf72e497b3b85cbeeab1f405b456401e08c78ce5b",
  "url": "https://osv.dev/vulnerability/CVE-2020-20136",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2020-20136",
    "summary": "QuantConnect Lean versions from 2.3.0.0 to 2.4.0.1 are affected by an insecure deserialization vulnerability due to insecure configuration of TypeNameHandling property in Json.NET library.",
    "evidence": "osv:CVE-2020-20136",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2020-20136",
      "aliases": [
        "CVE-2020-20136",
        "GHSA-ww7r-278h-48mh"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/quantconnect/lean",
              "type": "GIT",
              "events": [
                {
                  "introduced": "629d71a3eb20112d4a4bcbd37ba2bf715c64c202"
                },
                {
                  "last_affected": "64cf1ff870bd8670cb9a3c301258f597f51a9d8c"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:quantconnect:lean:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "2.3.0.0"
                      },
                      {
                        "last_affected": "2.4.0.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.4.0.1",
            "v2.4.0.0",
            "v2.3.0.3",
            "v2.3.0.2",
            "v2.3.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2020-20136.json"
          }
        }
      ],
      "modified": "2026-10-20T10:52:15.160820563Z",
      "provider": "osv",
      "references": [
        "https://github.com/QuantConnect/Lean/issues/3537"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2020-20136",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 383499,
  "published_at": "2020-12-14T19:15:12.613+00:00"
}