PYSEC-2021-142: pyyaml fixed in 5.4

PYSEC-2021-142 PUBLISHED CVSS 9.300000190734863 CRITICAL

Record from OSV · Published February 9, 2021

pyyaml is fixed in 5.4 (PyPI)

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.

Fixed versions

Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.

Package	Ecosystem	Fixed in
pyyaml	PyPI	5.4

Risk scores

CVSS 4.0

9.300000190734863

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

Affected products

Vendor	Product	Versions
PyPI	pyyaml	4.2b1, 0, 3.01

Timeline

Feb 9, 2021 CVE Published
Nov 8, 2023 CVE Updated

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References

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