CVE-2023-34611
📋 TL;DR
This vulnerability in mjson library versions through 1.4.1 allows attackers to cause denial of service or potentially other impacts by sending crafted JSON objects containing cyclic dependencies. Any application using vulnerable mjson versions for JSON parsing is affected.
💻 Affected Systems
- mjson
📦 What is this software?
Mjson by Mjson Project
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability due to infinite recursion or memory exhaustion, potentially leading to remote code execution if memory corruption occurs.
Likely Case
Denial of service causing application crashes or high resource consumption when processing malicious JSON input.
If Mitigated
Limited impact with proper input validation and resource limits in place.
🎯 Exploit Status
Proof of concept available in GitHub issue. Exploitation requires sending malicious JSON to vulnerable parser.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.4.2 or later
Vendor Advisory: https://github.com/bolerio/mjson/issues/40
Restart Required: Yes
Instructions:
1. Update mjson to version 1.4.2 or later. 2. Restart affected applications. 3. Test JSON parsing functionality.
🔧 Temporary Workarounds
Input validation and sanitization
allImplement strict input validation to reject JSON with cyclic dependencies before parsing.
Resource limiting
allConfigure memory and recursion limits for JSON parsing operations.
🧯 If You Can't Patch
- Implement WAF rules to block JSON payloads with cyclic dependency patterns
- Isolate vulnerable systems behind reverse proxies with request filtering
🔍 How to Verify
Check if Vulnerable:
Check if application uses mjson version <=1.4.1 via dependency manifest or package manager.Check Version:
Check package.json, requirements.txt, or equivalent for mjson versionVerify Fix Applied:
Verify mjson version is >=1.4.2 and test with known malicious JSON payloads.📡 Detection & Monitoring
Log Indicators:
- Application crashes during JSON parsing
- High memory usage spikes
- Stack overflow errors
Network Indicators:
- Incoming JSON payloads with circular references
- Repeated JSON parsing requests
SIEM Query:
search 'mjson' AND ('crash' OR 'memory' OR 'recursion')