{"id":"CVE-2019-20477","aliases":["GHSA-3pqx-4fqf-j49f","PYSEC-2020-176"],"url":"https://o3.security/vulnerability/CVE-2019-20477","summary":"Deserialization of Untrusted Data in PyYAML","details":"PyYAML 5.1 through 5.1.2 has insufficient restrictions on the load and load_all functions because of a class deserialization issue, e.g., Popen is a class in the subprocess module. NOTE: this issue exists because of an incomplete fix for CVE-2017-18342.","published":"2020-02-19T04:15:10.803Z","modified":"2026-07-08T05:56:27.741123677Z","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":null,"affectedPackages":[{"ecosystem":"PyPI","name":"pyyaml","fixedVersion":"5.2"}],"fix":null,"references":[{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/33VBUY73AA6CTTYL3LRWHNFDULV7PFPN/"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/52N5XS73Z5S4ZN7I7R56ICCPCTKCUV4H/"},{"type":"ADVISORY","url":"https://github.com/yaml/pyyaml/blob/master/CHANGES"},{"type":"EVIDENCE","url":"https://www.exploit-db.com/download/47655"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-08T05:56:27.741123677Z"}}