CVE-2025-0696
📋 TL;DR
CVE-2025-0696 is a NULL pointer dereference vulnerability in Cesanta Frozen JSON parsing library versions before 1.7. Attackers can crash applications using this library by sending specially crafted JSON input. This affects any software embedding vulnerable Frozen library versions.
💻 Affected Systems
- Cesanta Frozen JSON parsing library
⚠️ 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
Denial of service causing application crashes and service disruption
Likely Case
Application crashes requiring restart, potentially causing temporary service unavailability
If Mitigated
Minimal impact with proper input validation and error handling
🎯 Exploit Status
Simple exploitation via crafted JSON input, no authentication required if JSON parsing endpoint is exposed
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.7
Vendor Advisory: https://github.com/cesanta/frozen/releases/tag/1.7
Restart Required: Yes
Instructions:
1. Update Frozen library to version 1.7 or later. 2. Recompile applications using the library. 3. Restart affected services.
🔧 Temporary Workarounds
Input validation and sanitization
allImplement strict JSON input validation before passing to Frozen library
Error handling wrapper
allWrap Frozen library calls with exception/error handlers to prevent crashes
🧯 If You Can't Patch
- Implement network segmentation to limit access to JSON parsing endpoints
- Deploy web application firewall (WAF) with JSON parsing protection rules
🔍 How to Verify
Check if Vulnerable:
Check application dependencies for Frozen library version <1.7Check Version:
Check package manager or build configuration for Frozen library versionVerify Fix Applied:
Verify Frozen library version is 1.7 or higher in application dependencies📡 Detection & Monitoring
Log Indicators:
- Application crashes, segmentation faults, abnormal termination logs
Network Indicators:
- Unusual JSON payloads to parsing endpoints, repeated crash-inducing requests
SIEM Query:
source="application_logs" AND ("segmentation fault" OR "null pointer" OR "crash") AND process="*frozen*"