CVE-2021-29328
📋 TL;DR
CVE-2021-29328 is a buffer over-read vulnerability in Moddable's fxDebugThrow function that could allow attackers to read sensitive memory contents. This affects applications using Moddable v10.5.0 for embedded JavaScript development. The vulnerability could lead to information disclosure or potentially enable further exploitation.
💻 Affected Systems
- Moddable SDK
📦 What is this software?
Moddable by Moddable
⚠️ Risk & Real-World Impact
Worst Case
Memory disclosure leading to sensitive data exposure, potential information leak that could facilitate ASLR bypass or enable further exploitation chains
Likely Case
Application crash or denial of service due to invalid memory access, potential information disclosure from adjacent memory
If Mitigated
Minimal impact if debug functionality is disabled or proper memory protections are in place
🎯 Exploit Status
Exploitation requires triggering the specific debug function with crafted input; no public exploits have been documented
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v10.5.1 and later
Vendor Advisory: https://github.com/Moddable-OpenSource/moddable/issues/585
Restart Required: Yes
Instructions:
1. Update Moddable SDK to version 10.5.1 or later. 2. Rebuild and redeploy any applications using the vulnerable version. 3. Verify debug functionality is properly secured in production environments.
🔧 Temporary Workarounds
Disable Debug Functionality
allDisable or restrict access to debug features in production environments
Build with debug features disabled: xsbug = false in project configuration
🧯 If You Can't Patch
- Implement input validation and sanitization for all debug-related functionality
- Apply memory protection mechanisms and sandboxing where available
🔍 How to Verify
Check if Vulnerable:
Check Moddable SDK version: if using v10.5.0, you are vulnerableCheck Version:
Check package.json or build configuration for Moddable versionVerify Fix Applied:
Verify Moddable SDK version is 10.5.1 or later and rebuild applications📡 Detection & Monitoring
Log Indicators:
- Application crashes with memory access violations
- Unexpected debug function calls
Network Indicators:
- Unusual debug protocol traffic patterns
SIEM Query:
Process crashes with memory access violation errors in Moddable applications