CVE-2020-1747: Fedoraproject Fedora

Critical severity, CVSS 9.8. EPSS: 5.4% chance of exploitation in the next 30 days.

A vulnerability was discovered in the PyYAML library in versions before 5.3.1, 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. An attacker could use this flaw to execute arbitrary code on the system by abusing the python/object/new constructor.

Affected products

• Fedoraproject Fedora: version 30 only; version 31 only; version 32 only; version 33 only
• Opensuse Leap: version 15.1 only
• Oracle Communications Cloud Native Core Network Function Cloud Native Environment: version 22.1.0 only
• Pyyaml Pyyaml: from 5.1, before 5.3.1 (fixed in 5.3.1)

Published 2020-03-24. Last modified 2026-06-17.