{"cve":"CVE-2019-20477","nvd":{"published":"2020-02-19T04:15:10.803","modified":"2026-06-17T02:30:32.580","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-502"],"references":["https://github.com/yaml/pyyaml/blob/master/CHANGES","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/33VBUY73AA6CTTYL3LRWHNFDULV7PFPN/","https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/52N5XS73Z5S4ZN7I7R56ICCPCTKCUV4H/","https://www.exploit-db.com/download/47655","https://github.com/yaml/pyyaml/blob/master/CHANGES"],"products":["fedoraproject:fedora","pyyaml:pyyaml"],"source":"nvd","synced_at":"2026-10-19T21:02:53.949909883+00:00"},"epss":{"cve":"CVE-2019-20477","score":0.05114,"percentile":0.92382,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-3pqx-4fqf-j49f","url":"https://osv.dev/vulnerability/GHSA-3pqx-4fqf-j49f","summary":"Deserialization of Untrusted Data in PyYAML","modified":"2024-10-25T21:23:11.506576Z","packages":[{"ecosystem":"PyPI","name":"pyyaml","purl":"pkg:pypi/pyyaml","ranges":[">=5.1 <5.2"],"fixed":["5.2"]}]},{"id":"PYSEC-2020-176","url":"https://osv.dev/vulnerability/PYSEC-2020-176","summary":"","modified":"2023-11-08T04:01:30.627114Z","packages":[{"ecosystem":"PyPI","name":"pyyaml","purl":"pkg:pypi/pyyaml","ranges":[">=5.1 <5.2b1"],"fixed":["5.2b1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}