Your RSA-2048 keys break in 2030. Find every one of them before attackers do.
🐍
🐍 PyPI
Not in CISA KEV
CRITICAL severity

CVE-2020-13388 — jw-util

CRITICAL

CVE-2020-13388 is a critical-severity (CVSS 9.8) OS Command Injection vulnerability in jw-util. 2 public exploit references exist, so weaponization risk is real. A fix is available for jw-util — see the affected versions and patch details below.

OS Command Injection in jw.util

Also known asPYSEC-2020-341
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
2 known
Exploitation data as of Oct 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
4.5%probability of exploitation in next 30 days
Lower Risk+0.11%
Lower risk than most CVEs91th percentile — riskier than 91% of all scored CVEsHighest risk
1.65%2.83%4.02%5.20%2.3%4.5%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2020-13388 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🐍jw-util

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

An exploitable vulnerability exists in the configuration-loading functionality of the jw.util package before 2.3 for Python. When loading a configuration with FromString or FromStream with YAML, one can execute arbitrary Python code, resulting in OS command execution, because safe_load is not used.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIjw-utilall versions2.3pip install --upgrade 'jw-util==2.3'

Affected Products

1 product · 1 configurations
Application
jw.utilpython
< 2.3
range
Exploits & PoCs
2

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

An exploitable vulnerability exists in the configuration-loading functio…

joel-malwarebenchmark.github.ioNVDMay 2020

An exploitable vulnerability exists in the configuration-loading functio…

joel-malwarebenchmark.github.ioNVDMar 2023

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jw-util, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update jw-util to 2.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-13388 is resolved across your whole dependency graph.

  3. Workarounds

    Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Frequently Asked Questions

An exploitable vulnerability exists in the configuration-loading functionality of the jw.util package before 2.3 for Python. When loading a configuration with FromString or FromStream with YAML, one can execute arbitrary Python code, resulting in OS command execution, because safe_load is not used.
O3 Security · Impact-Aware SCA

Is CVE-2020-13388 in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works
CVE-2020-13388: jw-util Command Injection — Fixed in 2.3