CVE-2020-14343

critical

Description

A vulnerability was discovered in the PyYAML library in versions before 5.4, where it is susceptible to arbitrary code execution when it processes untrusted YAML files through the full_load method or with the FullLoader loader. Applications that use the library to process untrusted input may be vulnerable to this flaw. This flaw allows an attacker to execute arbitrary code on the system by abusing the python/object/new constructor. This flaw is due to an incomplete fix for CVE-2020-1747.

References

Advisories
More

https://www.oracle.com/security-alerts/cpujul2022.html

https://www.oracle.com/security-alerts/cpuapr2022.html

https://bugzilla.redhat.com/show_bug.cgi?id=1860466

https://github.com/Miahnation/devsecops-pipeline-demo

https://github.com/seal-sec-demo-2/Python-Example

https://github.com/c-fido/cve-triage-agent

https://github.com/Malatesh0811/reachable-cve

https://github.com/pmckone/Vulnerable-Dependency-Scanner

https://github.com/aymaan-balbale/cve-breaker

https://github.com/theocampos/gr4pe

https://github.com/fabriziosalmi/gitoma-bench-supply-chain

https://github.com/BiranPeretz/docling-core-CVE-2026-24009

https://github.com/sijie52/yasa-cve-2020-14343

https://github.com/GleidesonFr/libraries-vulnerabities

https://github.com/j4k0m/loader-CVE-2020-14343

https://github.com/raul23/pyyaml-CVE-2020-14343

https://github.com/advisories/GHSA-8q59-q68h-6hv4

https://github.com/yaml/pyyaml/issues/420

https://github.com/SeldonIO/seldon-core/issues/2252

Details

Source: Mitre, NVD

Published: 2021-02-09

Updated: 2026-06-17

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

CVSS v4

Base Score: 9.3

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Severity: Critical

EPSS

EPSS: 0.13704