CVE-2021-46170
📋 TL;DR
This CVE describes a use-after-free vulnerability in JerryScript's lexer component that could allow memory corruption. Attackers could potentially execute arbitrary code or cause denial of service by exploiting this flaw. Systems running vulnerable versions of JerryScript or applications embedding it are affected.
💻 Affected Systems
- JerryScript JavaScript engine
- IoT devices using JerryScript
- Embedded systems with JerryScript
📦 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 or denial of service, potentially leading to memory corruption that could be leveraged for further exploitation
If Mitigated
Contained application crash with no privilege escalation if proper sandboxing and memory protections are implemented
🎯 Exploit Status
Exploitation requires crafting malicious JavaScript that triggers the use-after-free condition
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after commit a6ab5e9
Vendor Advisory: https://github.com/jerryscript-project/jerryscript/issues/4917
Restart Required: Yes
Instructions:
1. Update JerryScript to latest version from official repository 2. Rebuild any applications using JerryScript 3. Restart affected services or devices
🔧 Temporary Workarounds
Disable JavaScript execution
allTemporarily disable JavaScript processing in affected systems if not essential
Memory protection hardening
linuxEnable ASLR and other memory protection mechanisms
sysctl -w kernel.randomize_va_space=2
🧯 If You Can't Patch
- Isolate affected systems from untrusted networks
- Implement strict input validation and sanitization for JavaScript processing
🔍 How to Verify
Check if Vulnerable:
Check JerryScript version/git commit hash against vulnerable commit a6ab5e9Check Version:
jerry --version or check git commit hash in sourceVerify Fix Applied:
Verify JerryScript version is newer than commit a6ab5e9📡 Detection & Monitoring
Log Indicators:
- Application crashes
- Memory access violation errors
- Unexpected process termination
Network Indicators:
- Unusual JavaScript payloads
- Repeated connection attempts to JerryScript endpoints
SIEM Query:
process_name:"jerry" AND (event_type:crash OR memory_violation)