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CRITICAL severity

CVE-2020-7771 — asciitable.js

CRITICALFix: victornpb/asciitable.js#1

CVE-2020-7771 is a critical-severity (CVSS 9.8) CWE-1321 vulnerability in asciitable.js. 1 public exploit reference exists, so weaponization risk is real. A fix is available for asciitable.js — see the affected versions and patch details below.

Prototype Pollution in asciitable.js

Also known asGHSA-5pxj-mhwj-x5gv
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
2.0%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs80th percentile — riskier than 80% of all scored CVEsHighest risk
0.00%0.82%1.64%2.46%0.4%2.0%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2020-7771 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 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

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

2other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
asciitable.jsnpm
70downloads / week

Description

The package asciitable.js before 1.0.3 is vulnerable to Prototype Pollution via the main function.

PoC

var a = require("asciitable.js"); 
var b = JSON.parse('{"__proto__":{"test":123}}'); 
a({},b); 
console.log({}.test)

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmasciitable.jsall versions1.0.3npm install asciitable.js@1.0.3

Affected Products

1 product · 1 configurations
Application
asciitable.jsasciitable.js_project
< 1.0.3
range
Exploits & PoCs
1

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

The package asciitable.js before 1.0.3 are vulnerable to Prototype Pollu…

snyk.ioNVDJan 2021

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update asciitable.js to 1.0.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-7771 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

The package asciitable.js before 1.0.3 is vulnerable to Prototype Pollution via the main function. ### PoC ```js var a = require("asciitable.js"); var b = JSON.parse('{"__proto__":{"test":123}}'); a({},b); console.log({}.test) ```
O3 Security · Impact-Aware SCA

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CVE-2020-7771: asciitable.js — Fixed in 1.0.3