CVE-2026-46440 — flowise

Detection Method: Kolega.dev Deep Code Scan

Description

The checkBasicAuth endpoint validates credentials in plaintext without rate limiting and with direct comparison.

Affected Code

public async checkBasicAuth(req: Request, res: Response) {
    const { username, password } = req.body
    if (username === process.env.FLOWISE_USERNAME && password === process.env.FLOWISE_PASSWORD) {
        return res.json({ message: 'Authentication successful' })

Evidence

Credentials are sent in plaintext in request body and compared directly without hashing. No rate limiting prevents brute force attacks. The endpoint returns different messages for success/failure, enabling enumeration.

Impact

Credential brute-forcing - attackers can attempt unlimited username/password combinations against the basic auth system. Successful attacks grant access to the application.

Recommendation

1. Implement rate limiting on this endpoint, 2) Use constant-time comparison to prevent timing attacks, 3) Consider using hashed comparison, 4) Return generic error messages, 5) Add logging for failed attempts.

Notes

The checkBasicAuth endpoint at line 128-135 has multiple security issues: (1) No rate limiting - the RateLimiterManager only applies to chatflow-specific endpoints, not auth endpoints. Attackers can perform unlimited brute force attempts. (2) Uses JavaScript === operator for comparison which is not constant-time, potentially enabling timing attacks. (3) Returns different messages for success ('Authentication successful') vs failure ('Authentication failed'), enabling credential enumeration. The endpoint compares plaintext credentials against environment variables FLOWISE_USERNAME and FLOWISE_PASSWORD. While this is basic auth for simpler deployments, the lack of rate limiting makes it actively exploitable for credential brute-forcing.