PyPI package

PyYAML 5.2.0 vulnerabilities, and the version that fixes all of them

PyYAML 5.2.0 has 2 known vulnerabilities (2 rated high or critical); 5.4 fixes all of them.

PyPI (opens in a new tab) describes it as “YAML parser and emitter for Python”

Known vulnerabilities: 2; 2 rated high or critical
Released: Dec 2, 2019; Latest is 6.0.3
Licence: MIT
OpenSSF Scorecard: 4.8/10; yaml/pyyaml (opens in a new tab)
Dependencies: None; Resolved by deps.dev

What to upgrade to

5.4 is the closest release with no known vulnerabilities.

5.4Upgrade to this
Fixes all 2 known vulnerabilities.
No known vulnerabilities
5.4.1
Newest 5.x release. Released Jan 20, 2021.
No known vulnerabilities
6.0.3
Latest release. Released Sep 25, 2025.
No known vulnerabilities

Hand the fix to your coding agent

One task with the upgrade, the file to change and why. Paste it into Claude Code, Cursor or Codex.

Findings

CriticalVulnerability
2 known vulnerabilities in pyyaml 5.2.0
EPSS: top 7%
2 rated high or critical. Most serious: CVE-2020-14343, Improper Input Validation in PyYAML. Upgrading to 5.4 fixes all of them.
5.2.05.4View advisory, source: OSV.dev (opens in a new tab)Upgrade notes (opens in a new tab)
LowOutdated
pyyaml 5.2.0 is 1 major version behind
Latest release is 6.0.3.
5.2.06.0.3Release notes, source: PyPI (opens in a new tab)Upgrade notes (opens in a new tab)

Every advisory for PyYAML 5.2.0

Known exploited first (CISA KEV), then by how likely they are to be exploited (FIRST EPSS), then by severity. Each id links to its OSV.dev record.

CriticalCVE-2020-14343 on OSV.dev (opens in a new tab)GHSA-8q59-q68h-6hv4EPSS: top 7%
Improper Input Validation in PyYAML
Fixed in 5.4. Published Mar 25, 2021.
CriticalCVE-2020-1747 on OSV.dev (opens in a new tab)GHSA-6757-jp84-gxfxEPSS: top 8%
Improper Input Validation in PyYAML
Fixed in 5.3.1. Published Apr 20, 2021.

Is PyYAML the only one?

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How this page is checked

StackPrism asks OSV.dev which advisories affect exactly PyYAML 5.2.0, merges duplicates filed under several ids, and ranks them with CISA’s Known Exploited Vulnerabilities list and FIRST EPSS. Release dates and deprecation come from deps.dev and PyPI. No AI writes this page: every sentence comes from that data, refreshed every few hours.

Last checked Oct 17, 2026, 06:35 UTC against PyPI, OSV.dev, deps.dev, CISA KEV and FIRST EPSS.