CVE-2020-26308
📋 TL;DR
CVE-2020-26308 is a Regular Expression Denial of Service (ReDoS) vulnerability in validate.js library versions 0.13.1 and earlier. Attackers can craft malicious input that causes excessive CPU consumption, potentially leading to service disruption. Any application using vulnerable versions of validate.js for input validation is affected.
💻 Affected Systems
- validate.js
📦 What is this software?
Validate.js by Validatejs
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability due to CPU exhaustion, potentially affecting all users of the application.
Likely Case
Degraded performance and intermittent service disruptions when attackers submit specially crafted input.
If Mitigated
Minimal impact with proper input validation limits and monitoring in place.
🎯 Exploit Status
Exploitation requires submitting specially crafted input to validation endpoints. Proof-of-concept examples are publicly available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: None available
Vendor Advisory: https://github.com/ansman/validate.js/issues/342
Restart Required: No
Instructions:
No official patch exists. Consider alternative validation libraries or implement workarounds.
🔧 Temporary Workarounds
Input length limiting
allLimit input length before validation to prevent ReDoS attacks
// JavaScript example: if (input.length > 1000) rejectInput();
Validation timeout
allImplement timeout mechanisms for validation operations
// Use Promise.race with timeout: Promise.race([validate(input), timeoutPromise])
🧯 If You Can't Patch
- Implement Web Application Firewall (WAF) rules to block suspicious input patterns
- Monitor CPU usage and implement rate limiting on validation endpoints
🔍 How to Verify
Check if Vulnerable:
Check package.json or node_modules for validate.js version 0.13.1 or earlierCheck Version:
npm list validate.jsVerify Fix Applied:
Verify validate.js is not used or has been replaced with alternative validation library📡 Detection & Monitoring
Log Indicators:
- Unusually long validation times
- High CPU usage spikes
- Repeated validation failures
Network Indicators:
- Multiple requests with similar patterns to validation endpoints
- Unusually large payloads to validation endpoints
SIEM Query:
source="application" AND (message="validate.js" OR message="validation timeout") AND cpu_usage>90