CVE-2026-69254

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.3, executeJavaScriptCode() accepted caller-provided nodeVMOptions and merged them over the default NodeVM security settings in packages/components/src/utils.ts. An authenticated attacker reaching packages/server/src/routes/node-custom-functions/index.ts could run a custom function that imported flowise-components/dist/src/utils.js, called executeJavaScriptCode() again with nodeVMOptions.require.builtin set to allow all built-in modules, and then required child_process to execute arbitrary system commands as root on the Flowise server. This issue is fixed in version 3.1.3.

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.3, executeJavaScriptCode() accepted caller-provided nodeVMOptions and merged them over the default NodeVM security settings in packages/components/src/utils.ts. An authenticated attacker reaching packages/server/src/routes/node-custom-functions/index.ts could run a custom function that imported flowise-components/dist/src/utils.js, called executeJavaScriptCode() again with nodeVMOptions.require.builtin set to allow all built-in modules, and then required child_process to execute arbitrary system commands as root on the Flowise server. This issue is fixed in version 3.1.3.

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)
…

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.3, executeJavaScriptCode() accepted caller-provided nodeVMOptions and merged them over the default NodeVM security settings in packages/components/src/utils.ts. An authenticated attacker reaching packages/server/src/routes/node-custom-functions/index.ts could run a custom function that imported flowise-components/dist/src/utils.js, called executeJavaScriptCode() again with nodeVMOptions.require.builtin set to allow all built-in modules, and then required child_process to execute arbitrary system commands as root on the Flowise server. This issue is fixed in version 3.1.3.

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.3, executeJavaScriptCode() accepted caller-provided nodeVMOptions and merged them over the default NodeVM security settings in packages/components/src/utils.ts. An authenticated attacker reaching packages/server/src/routes/node-custom-functions/index.ts could run a custom function that imported flowise-components/dist/src/utils.js, called executeJavaScriptCode() again with nodeVMOptions.require.builtin set to allow all built-in modules, and then required child_process to execute arbitrary system commands as root on the Flowise server. This issue is fixed in version 3.1.3.

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)
…