Improper Input Validation in PyYAML
Published Mar 24, 2020 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
Improper Input Validation in PyYAML
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
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.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
- FEDORA-2020-40c35d7b37 ↗
- FEDORA-2020-bdb0bfa928 ↗
- FEDORA-2020-e9741a6a15 ↗
- openSUSE-SU-2020:0507 ↗
- openSUSE-SU-2020:0630 ↗
- FEDORA-2021-3342569a0f ↗
- FEDORA-2021-eed7193502 ↗
- www.oracle.com ↗
- bugzilla.redhat.com ↗
- Source repository ↗
Record history
Published Mar 24, 2020 · Last refreshed Nov 3, 2026