{"id":"CVE-2020-20136","aliases":["GHSA-ww7r-278h-48mh"],"url":"https://o3.security/vulnerability/CVE-2020-20136","summary":"QuantConnect Lean vulnerable to insecure deserialization","details":"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.","published":"2020-12-14T19:15:12.613Z","modified":"2026-07-09T06:35:05.640388Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"NuGet","name":"QuantConnect.Common","fixedVersion":null}],"fix":null,"references":[{"type":"EVIDENCE","url":"https://github.com/QuantConnect/Lean/issues/3537"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T06:35:05.640388Z"}}