CVE-2019-20477

CRITICAL

Pyyaml < 5.1.2 - Insecure Deserialization

Title source: rule

Description

PyYAML 5.1 through 5.1.2 has insufficient restrictions on the load and load_all functions because of a class deserialization issue, e.g., Popen is a class in the subprocess module. NOTE: this issue exists because of an incomplete fix for CVE-2017-18342.

References (4)

[Release Notes, Third Party Advisory] https://github.com/yaml/pyyaml/blob/master/CHANGES

View Writeup ZIP pw:eip

[Exploit, Third Party Advisory, VDB Entry] https://www.exploit-db.com/download/47655

[Mailing List, Third Party Advisory] https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/33VBUY73AA6CTTYL3LRWHNFDULV7PFPN/

[Mailing List, Third Party Advisory] https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/52N5XS73Z5S4ZN7I7R56ICCPCTKCUV4H/

Scores

CVSS v3 9.8

EPSS 0.0043

EPSS Percentile 62.5%

Attack Vector NETWORK

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

Classification

CWE

CWE-502

Status published

Affected Products (4)

pyyaml/pyyaml < 5.1.2

fedoraproject/fedora

fedoraproject/fedora

pypi/pyyaml < 5.2PyPI

Timeline

Published Feb 19, 2020

Tracked Since Feb 18, 2026