CVE-2025-62496
📋 TL;DR
This vulnerability allows attackers to trigger a heap out-of-bounds write by providing an excessively large BigInt string to QuickJS. Successful exploitation could lead to remote code execution or denial of service. Any system using QuickJS for JavaScript execution is potentially affected.
💻 Affected Systems
- QuickJS JavaScript Engine
- Applications embedding QuickJS
📦 What is this software?
Quickjs by Quickjs Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise
Likely Case
Denial of service through application crashes or memory corruption
If Mitigated
Application crash without code execution if memory protections are enabled
🎯 Exploit Status
Exploitation requires crafting specific large numeric strings but doesn't require authentication
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check QuickJS changelog for specific version
Vendor Advisory: https://bellard.org/quickjs/Changelog
Restart Required: Yes
Instructions:
1. Update QuickJS to latest version from official repository
2. Recompile any applications using QuickJS
3. Restart affected services
🔧 Temporary Workarounds
Input validation
allValidate BigInt string length before processing
Implement input validation to reject strings longer than 79,536,431 digits
Disable BigInt parsing
allDisable BigInt functionality if not required
Configure QuickJS to disable BigInt support
🧯 If You Can't Patch
- Implement strict input validation for all BigInt string inputs
- Use memory protection mechanisms like ASLR and DEP
🔍 How to Verify
Check if Vulnerable:
Test with a crafted BigInt string of 79,536,432+ digits and monitor for crashesCheck Version:
quickjs --version or check embedded version in applicationsVerify Fix Applied:
Verify QuickJS version is updated and test with same crafted input📡 Detection & Monitoring
Log Indicators:
- Application crashes
- Memory access violation errors
- Unusual large numeric string inputs
Network Indicators:
- Large payloads containing numeric strings
SIEM Query:
search 'quickjs' AND ('crash' OR 'segmentation fault' OR 'access violation')