CVE-2026-23830
📋 TL;DR
SandboxJS versions before 0.8.26 have a critical sandbox escape vulnerability that allows attackers to execute arbitrary code outside the sandbox context. This occurs because AsyncFunction, GeneratorFunction, and AsyncGeneratorFunction constructors weren't properly isolated, enabling attackers to access the host environment's native constructors. Any application using vulnerable SandboxJS versions for JavaScript sandboxing is affected.
💻 Affected Systems
- SandboxJS
📦 What is this software?
Sandboxjs by Nyariv
⚠️ Risk & Real-World Impact
Worst Case
Complete host environment compromise with remote code execution, allowing attackers to execute arbitrary commands, access sensitive data, and potentially pivot to other systems.
Likely Case
Remote code execution within the application context, leading to data theft, privilege escalation, or complete application takeover.
If Mitigated
Limited impact if sandbox is only used for non-critical operations with minimal privileges and network access restrictions.
🎯 Exploit Status
The vulnerability is well-documented with public proof-of-concept available in the security advisory. Exploitation requires the ability to execute JavaScript within the sandbox, which is typically available to users in affected applications.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.8.26
Vendor Advisory: https://github.com/nyariv/SandboxJS/security/advisories/GHSA-wxhw-j4hc-fmq6
Restart Required: Yes
Instructions:
1. Update SandboxJS dependency to version 0.8.26 or later
2. Update package.json: "sandboxjs": "^0.8.26"
3. Run npm update sandboxjs or yarn upgrade sandboxjs
4. Restart the application to load the updated library
🔧 Temporary Workarounds
Disable sandbox execution
allTemporarily disable execution of untrusted JavaScript through SandboxJS until patching is complete
// In application code, disable sandbox execution or implement alternative validation
🧯 If You Can't Patch
- Implement strict input validation to prevent malicious JavaScript from reaching the sandbox
- Run the application with minimal privileges and network restrictions to limit potential damage
🔍 How to Verify
Check if Vulnerable:
Check package.json or node_modules/sandboxjs/package.json for version number less than 0.8.26Check Version:
npm list sandboxjs | grep sandboxjsVerify Fix Applied:
Verify SandboxJS version is 0.8.26 or higher and test sandbox execution with known exploit patterns📡 Detection & Monitoring
Log Indicators:
- Unusual JavaScript execution patterns
- Attempts to access AsyncFunction or similar constructors
- Unexpected process spawns or network connections from application
Network Indicators:
- Outbound connections from application to unexpected destinations
- Unusual data exfiltration patterns
SIEM Query:
process.name:"node" AND (process.cmdline:"AsyncFunction" OR process.cmdline:"GeneratorFunction")