CVE-2021-46324
📋 TL;DR
Espruino 2v11.251 contains a stack buffer overflow vulnerability in the jsvNewFromString function in src/jsvar.c. This allows attackers to execute arbitrary code or cause denial of service by providing specially crafted input. Anyone using Espruino JavaScript interpreter version 2v11.251 is affected.
💻 Affected Systems
- Espruino JavaScript interpreter
📦 What is this software?
Espruino by Espruino
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or persistent backdoor installation.
Likely Case
Denial of service causing Espruino interpreter crashes and application disruption.
If Mitigated
Limited impact with proper input validation and memory protection mechanisms in place.
🎯 Exploit Status
Proof of concept exists in GitHub issue #2121. Exploitation requires ability to supply malicious input to the vulnerable function.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 2v11.251
Vendor Advisory: https://github.com/espruino/Espruino/issues/2121
Restart Required: Yes
Instructions:
1. Update Espruino to latest version. 2. Recompile any applications using Espruino. 3. Restart affected services.
🔧 Temporary Workarounds
Input validation and sanitization
allImplement strict input validation for all data passed to jsvNewFromString function
Memory protection controls
allEnable stack protection (ASLR, DEP) on systems running Espruino
🧯 If You Can't Patch
- Isolate Espruino instances in restricted containers or sandboxes
- Implement network segmentation to limit access to vulnerable systems
🔍 How to Verify
Check if Vulnerable:
Check Espruino version: if running 2v11.251, system is vulnerableCheck Version:
espruino --version or check application dependenciesVerify Fix Applied:
Verify Espruino version is newer than 2v11.251 and test with known malicious inputs📡 Detection & Monitoring
Log Indicators:
- Espruino process crashes
- Memory access violation errors
- Unusual input patterns to JavaScript interpreter
Network Indicators:
- Unexpected network connections from Espruino processes
- Traffic patterns suggesting exploitation attempts
SIEM Query:
process_name:"espruino" AND (event_type:"crash" OR error_code:"ACCESS_VIOLATION")