Flowise Allows Mass Assignment in `/api/v1/leads` Endpoint

## Summary **A Mass Assignment vulnerability in the `/api/v1/leads` endpoint allows any unauthenticated user to control internal entity fields (`id`, `createdDate`, `chatId`) by including them in the request body.** The endpoint uses `Object.assign()` to copy all properties from the request body to the Lead entity without any input validation or field filtering. This allows attackers to bypass auto-generated fields and inject arbitrary values. | Field | Value | |-------|-------| | **Vulnerability Type** | Mass Assignment | | **CWE ID** | [CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes](https://cwe.mitre.org/data/definitions/915.html) | | **Authentication Required** | None | | **Affected Endpoint** | `POST /api/v1/leads` | --- ## Details ### Root Cause The vulnerability exists in `/packages/server/src/services/leads/index.ts` at lines 27-28: ```typescript // File: /packages/server/src/services/leads/index.ts // Lines 23-38 const createLead = async (body: Partial<ILead>) => { try { const chatId = body.chatId ?? uuidv4() const newLead = new Lead() Object.assign(newLead, body) // ← VULNERABILITY: All properties copied! Object.assign(newLead, { chatId }) const appServer = getRunningExpressApp() const lead = appServer.AppDataSource.getRepository(Lead).create(newLead) const dbResponse = await appServer.AppDataSource.getRepository(Lead).save(lead) return dbResponse } catch (error) { throw new InternalFlowiseError(...) } } ``` The `Object.assign(newLead, body)` on line 28 copies **ALL** properties from the request body to the Lead entity, including: - `id` - The primary key (should be auto-generated) - `createdDate` - The creation timestamp (should be auto-generated) - `chatId` - The chat identifier ### Lead Entity Definition The Lead entity at `/packages/server/src/database/entities/Lead.ts` uses TypeORM decorators that should auto-generate these fields: ```typescript // File: /packages/server/src/database/entities/Lead.ts @Entity() export class Lead implements ILead { @PrimaryGeneratedColumn('uuid') // Should be auto-generated! id: string @Column() name?: string @Column() email?: string @Column() phone?: string @Column() chatflowid: string @Column() chatId: string @CreateDateColumn() // Should be auto-generated! createdDate: Date } ``` However, `Object.assign()` overwrites these fields before they are saved, bypassing the auto-generation. ### Why the Endpoint is Publicly Accessible The `/api/v1/leads` endpoint is whitelisted in `/packages/server/src/utils/constants.ts`: ```typescript // File: /packages/server/src/utils/constants.ts // Line 20 export const WHITELIST_URLS = [ // ... other endpoints ... '/api/v1/leads', // ← No authentication required // ... more endpoints ... ] ``` --- ## Proof of Concept <img width="1585" height="817" alt="Screenshot 2025-12-26 at 2 28 00 PM" src="https://github.com/user-attachments/assets/807984e7-ae4f-4e8a-85b7-057d6ac42ff5" /> ### Prerequisites - Docker and Docker Compose installed - curl installed ### Step 1: Start Flowise Create a `docker-compose.yml`: ```yaml services: flowise: image: flowiseai/flowise:latest restart: unless-stopped environment: - PORT=3000 - DATABASE_PATH=/root/.flowise - DATABASE_TYPE=sqlite - CORS_ORIGINS=* - DISABLE_FLOWISE_TELEMETRY=true ports: - '3000:3000' volumes: - flowise_data:/root/.flowise entrypoint: /bin/sh -c "sleep 3; flowise start" volumes: flowise_data: ``` Start the container: ```bash docker compose up -d # Wait for Flowise to be ready (about 1-2 minutes) curl http://localhost:3000/api/v1/ping ``` ### Step 2: Baseline Test - Normal Lead Creation First, create a normal lead to see expected behavior: ```bash curl -X POST http://localhost:3000/api/v1/leads \

CVSS 3.0

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L

Severity from

GitHub (reviewed advisory)

Weakness

CWE-915

Also known as

CVE-2026-30822

• github.com/FlowiseAI/Flowise/security/advisories/GHSA-mq4r-h2gh-qv7x
• nvd.nist.gov/vuln/detail/CVE-2026-30822
• github.com/FlowiseAI/Flowise
• github.com/FlowiseAI/Flowise/releases/tag/flowise%403.0.13