CVE-2020-7774
📋 TL;DR
CVE-2020-7774 is a prototype pollution vulnerability in the y18n npm package that allows attackers to inject properties into JavaScript objects, potentially leading to remote code execution or denial of service. This affects applications using vulnerable versions of y18n, which is commonly used by command-line tools like yargs. The vulnerability can be exploited through specially crafted input to functions that parse locale files.
💻 Affected Systems
- y18n npm package
- Applications using y18n (including yargs command-line tools)
📦 What is this software?
Graalvm by Oracle
Graalvm by Oracle
Graalvm by Oracle
Sinec Infrastructure Network Services by Siemens
View all CVEs affecting Sinec Infrastructure Network Services →
Y18n by Y18n Project
Y18n by Y18n Project
Y18n by Y18n Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Denial of service, application crashes, or limited data manipulation depending on application context.
If Mitigated
Limited impact with proper input validation and sandboxing, potentially only causing application instability.
🎯 Exploit Status
Proof-of-concept code is publicly available in GitHub issues. Exploitation requires the application to process malicious locale files.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: y18n 3.2.2, 4.0.1, or 5.0.5
Vendor Advisory: https://github.com/yargs/y18n/security/advisories/GHSA-c4w7-x5m7-9r5h
Restart Required: Yes
Instructions:
1. Update y18n dependency in package.json to 3.2.2, 4.0.1, or 5.0.5. 2. Run 'npm update y18n' or 'yarn upgrade y18n'. 3. Restart the application.
🔧 Temporary Workarounds
Input validation for locale files
allValidate and sanitize all user input before passing to y18n functions.
🧯 If You Can't Patch
- Implement strict input validation for any data passed to y18n locale loading functions.
- Run the application in a sandboxed environment with limited permissions.
🔍 How to Verify
Check if Vulnerable:
Check package.json or run 'npm list y18n' to see installed version. If version is below 3.2.2, between 4.0.0-4.0.0, or between 5.0.0-5.0.4, it's vulnerable.Check Version:
npm list y18n | grep y18nVerify Fix Applied:
After updating, run 'npm list y18n' to confirm version is 3.2.2, 4.0.1, or 5.0.5. Test application functionality with locale files.📡 Detection & Monitoring
Log Indicators:
- Unexpected application crashes
- Errors related to object property assignment
- Unusual locale file loading patterns
Network Indicators:
- Unusual requests to endpoints that load locale files
SIEM Query:
source="application_logs" AND ("y18n" OR "locale" OR "prototype") AND ("error" OR "crash")🔗 References
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- https://github.com/yargs/y18n/issues/96
- https://github.com/yargs/y18n/pull/108
- https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1038306
- https://snyk.io/vuln/SNYK-JS-Y18N-1021887
- https://www.oracle.com/security-alerts/cpuApr2021.html
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- https://github.com/yargs/y18n/issues/96
- https://github.com/yargs/y18n/pull/108
- https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1038306
- https://snyk.io/vuln/SNYK-JS-Y18N-1021887
- https://www.oracle.com/security-alerts/cpuApr2021.html
