GHSA-c4w7-xm78-47vh is a high-severity (CVSS 7.3) CWE-1321 vulnerability in y18n. 3 public exploit references exist, so weaponization risk is real. A fix is available for y18n — see the affected versions and patch details below.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-c4w7-xm78-47vh by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
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.
y18nnpmDescription
Overview
The npm package y18n before versions 3.2.2, 4.0.1, and 5.0.5 is vulnerable to Prototype Pollution.
POC
const y18n = require('y18n')();
y18n.setLocale('__proto__');
y18n.updateLocale({polluted: true});
console.log(polluted); // true
Recommendation
Upgrade to version 3.2.2, 4.0.1, 5.0.5 or later.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | y18n | all versions | 3.2.2npm install y18n@3.2.2 |
| 📦npm | y18n | ≥ 4.0.0&&< 4.0.1 | 4.0.1npm install y18n@4.0.1 |
| 📦npm | y18n | ≥ 5.0.0&&< 5.0.5 | 5.0.5npm install y18n@5.0.5 |
Affected Products
graalvmoraclesinec infrastructure network servicessiemensy18ny18n_projectResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for y18n, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update y18n to 3.2.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c4w7-xm78-47vh is resolved across your whole dependency graph.
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.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
In OpenShift Container Platform (OCP), OpenShift ServiceMesh (OSSM) and OpenShift distributed tracing the affected components are behind OpenShift OAuth authentication. This restricts access to the vulnerable nodejs-y18n library to authenticated users only, therefore the impact is Low. In Red Hat OpenShift Container…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 8 | nodejs:12-8030020201124152102.229f0a1c | RHSA-2020:5499 |
| Red Hat Enterprise Linux 8 | nodejs:10-8030020210118191659.229f0a1c | RHSA-2021:0548 |
| Red Hat Enterprise Linux 8 | nodejs:14-8030020210126165503.229f0a1c | RHSA-2021:0551 |
| Red Hat OpenShift Container Platform 4.7 | openshift4/ose-grafana:v4.7.0-202102130115.p0 | RHSA-2020:5633 |
| Red Hat OpenShift Container Platform 4.8 | openshift4/ose-thanos-rhel8:v4.8.0-202106291913.p0.git.c358e96.assembly.stream | RHSA-2021:2438 |
| Red Hat OpenShift Container Storage 4.7.0 on RHEL-8 | ocs4/mcg-core-rhel8:5.7.0-60.2c1fdb0.5.7 | RHSA-2021:2041 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | rh-nodejs12-nodejs-0:12.19.1-2.el7 | RHSA-2020:5305 |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | rh-nodejs14-nodejs-0:14.15.4-2.el7 | RHSA-2021:0421 |
Frequently Asked Questions
Is GHSA-c4w7-xm78-47vh in your dependencies?
Find it across npm, including transitive dependencies.