CVE-2020-14163
📋 TL;DR
This CVE describes a use-after-free vulnerability in JerryScript's garbage collector that can lead to memory corruption. Attackers could exploit this to cause denial of service, information disclosure, or potentially execute arbitrary code. This affects systems running applications that use vulnerable versions of the JerryScript JavaScript engine.
💻 Affected Systems
- JerryScript JavaScript engine
📦 What is this software?
Jerryscript by Jerryscript
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or persistent backdoor installation.
Likely Case
Application crash causing denial of service, memory corruption leading to information disclosure, or limited code execution within the JavaScript engine context.
If Mitigated
Application instability or crashes without data compromise if proper sandboxing and memory protections are in place.
🎯 Exploit Status
Exploitation requires crafting specific JavaScript to trigger the garbage collection timing issue. No public exploit code has been identified, but the vulnerability is well-documented in the source code commits.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: JerryScript after commit c2b662170245a16f46ce02eae68815c325d99821
Vendor Advisory: https://github.com/jerryscript-project/jerryscript/commit/c2b662170245a16f46ce02eae68815c325d99821
Restart Required: Yes
Instructions:
1. Update JerryScript to version after commit c2b662170245a16f46ce02eae68815c325d99821. 2. Recompile any applications using JerryScript with the updated library. 3. Restart affected services or devices.
🔧 Temporary Workarounds
Disable JavaScript execution
allIf JerryScript functionality is not essential, disable JavaScript execution in affected applications
Application-specific configuration
Memory protection hardening
linuxEnable ASLR and other memory protection mechanisms to reduce exploit impact
echo 2 > /proc/sys/kernel/randomize_va_space
sysctl -w kernel.exec-shield=1
🧯 If You Can't Patch
- Isolate affected systems in network segments with strict access controls
- Implement application allowlisting to prevent unauthorized JavaScript execution
🔍 How to Verify
Check if Vulnerable:
Check JerryScript version: jerry --version or examine library files for version 2.2.0Check Version:
jerry --version 2>/dev/null || strings /path/to/jerryscript/library | grep -i versionVerify Fix Applied:
Verify JerryScript version is after commit c2b662170245a16f46ce02eae68815c325d99821📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults
- Memory access violation errors
- Unexpected garbage collection behavior
Network Indicators:
- Unusual JavaScript payloads sent to embedded devices
- Traffic patterns targeting JerryScript interfaces
SIEM Query:
source="application.log" AND ("segmentation fault" OR "memory violation" OR "jerryscript")🔗 References
- https://github.com/jerryscript-project/jerryscript/commit/c2b662170245a16f46ce02eae68815c325d99821
- https://github.com/jerryscript-project/jerryscript/issues/3804
- https://github.com/jerryscript-project/jerryscript/commit/c2b662170245a16f46ce02eae68815c325d99821
- https://github.com/jerryscript-project/jerryscript/issues/3804
