CVE-2025-3197
📋 TL;DR
CVE-2025-3197 is a prototype pollution vulnerability in the expand-object npm package that allows attackers to modify JavaScript object prototypes by controlling input to the expand() function. This affects any application using expand-object version 0.0.0 or later to parse user-controlled data. Attackers can potentially execute arbitrary code, modify application behavior, or cause denial of service.
💻 Affected Systems
- expand-object npm package
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Application instability, denial of service, or privilege escalation within the affected application.
If Mitigated
Limited impact with proper input validation and sandboxing, potentially only causing application crashes.
🎯 Exploit Status
Proof of concept available in security advisories. Exploitation requires attacker to control input to expand() function.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check for updated version from maintainer (no specific version indicated in provided references)
Vendor Advisory: https://security.snyk.io/vuln/SNYK-JS-EXPANDOBJECT-5821390
Restart Required: Yes
Instructions:
1. Check current expand-object version. 2. Update to patched version when available. 3. Restart all affected Node.js applications. 4. Test functionality after update.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement strict input validation to reject any input containing __proto__ or constructor properties
Use Object.create(null)
allCreate objects without prototype chain using Object.create(null) before passing to expand()
const safeObject = Object.create(null);
const result = expand(input, safeObject);
🧯 If You Can't Patch
- Implement strict input validation to reject any keys containing __proto__, constructor, or prototype
- Isolate affected applications in containers or VMs with minimal privileges and network access
🔍 How to Verify
Check if Vulnerable:
Check package.json for expand-object dependency and verify version is 0.0.0 or laterCheck Version:
npm list expand-objectVerify Fix Applied:
After update, test with malicious input containing __proto__ properties to ensure they are rejected📡 Detection & Monitoring
Log Indicators:
- Unusual application crashes
- Unexpected property modifications in objects
- Error logs mentioning prototype pollution
Network Indicators:
- Unusual HTTP requests containing __proto__ in parameters
- Suspicious input patterns to API endpoints using expand-object
SIEM Query:
search for 'expand-object' in application logs AND (__proto__ OR constructor OR prototype) in request parameters