CVE-2021-43453
📋 TL;DR
A heap-based buffer overflow vulnerability in JerryScript 2.4.0 and earlier allows attackers to execute arbitrary code or cause denial of service via specially crafted JavaScript code. This affects any application or device using vulnerable versions of the JerryScript JavaScript engine, particularly IoT devices and embedded systems.
💻 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 device takeover
Likely Case
Denial of service causing application crashes or device instability
If Mitigated
Limited impact if proper input validation and memory protections are in place
🎯 Exploit Status
Similar to CVE-2020-29657; exploitation requires crafting malicious JavaScript to trigger the parser vulnerability
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: JerryScript 2.4.1 or later
Vendor Advisory: https://github.com/jerryscript-project/jerryscript/issues/4754
Restart Required: Yes
Instructions:
1. Update JerryScript to version 2.4.1 or later. 2. Rebuild any applications using JerryScript. 3. Restart affected services or devices.
🔧 Temporary Workarounds
Input validation and sanitization
allImplement strict validation of JavaScript input before passing to JerryScript parser
Memory protection controls
allEnable ASLR, DEP, and other memory protection mechanisms where supported
🧯 If You Can't Patch
- Network segmentation to isolate vulnerable devices from untrusted networks
- Implement strict input filtering and sandboxing for JavaScript execution
🔍 How to Verify
Check if Vulnerable:
Check JerryScript version in use; versions 2.4.0 or earlier are vulnerableCheck Version:
jerry --version or check build configurationVerify Fix Applied:
Verify JerryScript version is 2.4.1 or later and test with known exploit payloads📡 Detection & Monitoring
Log Indicators:
- Application crashes, memory access violations, abnormal parser errors
Network Indicators:
- Unusual JavaScript payloads targeting JerryScript endpoints
SIEM Query:
source="application_logs" AND ("jerryscript" OR "parser_parse_for_statement_start") AND ("segfault" OR "buffer overflow" OR "access violation")