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MEDIUM severity

CVE-2021-23443 — edge.js

MEDIUMFix: edge-js/edge@fa2c7fd

CVE-2021-23443 is a medium-severity (CVSS 6.1) CWE-843 vulnerability in edge.js. 1 public exploit reference exists, so weaponization risk is real. A fix is available for edge.js — see the affected versions and patch details below.

Cross-site Scripting in edge.js

Also known asGHSA-55r9-7mf8-m382SNYK-JS-EDGEJS-1579556
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.9%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk
0.00%0.47%0.94%1.41%0.2%0.9%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2021-23443 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.

67other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
edge.jsnpm
81Kdownloads / week

Description

Edge is a logical and batteries included template engine for Node.js. This affects the package edge.js before 5.3.2. A type confusion vulnerability can be used to bypass input sanitization when the input to be rendered is an array (instead of a string or a SafeValue), even if {{ }} are used.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmedge.jsall versions5.3.2npm install edge.js@5.3.2

Affected Products

1 product · 1 configurations
Application
edgeadonisjs
< 5.3.2
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.

This affects the package edge.js before 5.3.2. A type confusion vulnerab…

snyk.ioNVDSep 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 edge.js, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update edge.js to 5.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-23443 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

Edge is a logical and batteries included template engine for Node.js. This affects the package edge.js before 5.3.2. A type confusion vulnerability can be used to bypass input sanitization when the input to be rendered is an array (instead of a string or a SafeValue), even if `{{ }}` are used.
O3 Security · Impact-Aware SCA

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CVE-2021-23443: edge.js — Fixed in 5.3.2