Remote code execution in PyYAML parser and emitter for Python

Published: 2020-03-09 | Updated: 2020-07-15
Risk High
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2020-1747
Exploitation vector Network
Public exploit N/A
Vulnerable software
Web applications / Modules and components for CMS

Vendor The YAML Project

Security Bulletin

This security bulletin contains one high risk vulnerability.

1) Input validation error

EUVDB-ID: #VU25823

Risk: High


CVE-ID: CVE-2020-1747

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No


The vulnerability allows a remote attacker to execute arbitrary code on the target system.

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


Install update from vendor's website.

Vulnerable software versions

PyYAML: 3.01 - 5.3

CPE2.3 External links

Q & A

Can this vulnerability be exploited remotely?

Is there known malware, which exploits this vulnerability?