#VU54520 Input validation error in PyYAML - CVE-2020-14343 

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Main Vulnerability Database Vulnerabilities #VU54520

#VU54520 Input validation error in PyYAML - CVE-2020-14343

Published: July 4, 2021 / Updated: November 28, 2025


Vulnerability identifier: #VU54520
Vulnerability risk: High
CVSSv4.0: 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/E:P/U:Amber
CVE-ID: CVE-2020-14343
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability: Public exploit is available
Vulnerable software:
PyYAML
Software vendor:
The YAML Project

Description

The vulnerability allows a remote attacker to compromise the affected system.

The vulnerability exists due to insufficient validation of user-supplied input when processing untrusted YAML files through the full_load method or with the FullLoader loader. A remote attacker can pass specially crafted input to the application and execute arbitrary code on the system by abusing the python/object/new constructor.

Note, the vulnerability exists due to incomplete patch for vulnerability #VU25823.


Remediation

Install updates from vendor's website.

External links