SB2021070403 - Remote code execution in PyYAML for Python
Published: July 4, 2021 Updated: November 28, 2025
Security Bulletin ID
SB2021070403
Severity
High
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Input validation error (CVE-ID: CVE-2020-14343)
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 update from vendor's website.