fkie_cve-2026-56682

9Router is an AI router & token saver. Prior to 0.5.6, 9Router deployments that allow requests to reach Next.js without the sanitizing custom-server.js wrapper use the client-supplied X-9r-Real-Ip value as the bucket key in getClientIp, checkLock, and recordFail in src/lib/auth/loginLimiter.js for POST /api/auth/login. A remote unauthenticated attacker can rotate the header on every password guess so each request uses a new failed-attempt bucket and the five-attempt progressive lockout never returns HTTP 429. This permits unthrottled password guessing against the dashboard login and can lead to an administrative session if the password is recovered. This issue is fixed in version 0.5.6.

GHSA-32gc-64m7-hj7v — 9Router has a Login Brute-Force Lockout Bypass via Spoofable X-9r-Real-Ip Header

Affected: npm: 9router

# Summary

9router enforces a progressive login lockout (5 failed attempts → temporary 30s+ lock) keyed on the client IP. The client IP used for this limiter is taken from the X-9r-Real-Ip request header, which is intended to be set only by the bundled custom-server.js layer from the unspoofable TCP socket address. In deployment modes where requests reach Next.js directly, a remote attacker controls this header and can assign a unique value to every request. Because each distinct header value maps to a fresh limiter bucket, the lockout never triggers, enabling unlimited password guessing against the dashboard login endpoint. This was reproduced against a live instance: a fixed header value was locked out (429) after 5 attempts, while rotating the header produced unlimited 401 responses with no lockout.

# Affected Component

- `src/lib/auth/loginLimiter.js` - `getClientIp()` — derives the rate-limit bucket key from the client-supplied `X-9r-Real-Ip` header - `checkLock()` / `recordFail()` — per-IP progressive lockout (`MAX_FAILS_BEFORE_LOCK = 5`) - `src/app/api/auth/login/route.js` — login endpoint protected by the above limiter

# Root Cause

The brute-force protection partitions failed-attempt counters by client IP, but obtains that IP from a client-controllable HTTP header rather than from the transport layer. `getClientIp()` returns the value of `X-9r-Real-Ip` directly. The design assumes this header is produced and sanitized only by the trusted `custom-server.js` wr…

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fkie_cve-2026-56682

GHSA-32gc-64m7-hj7v — 9Router has a Login Brute-Force Lockout Bypass via Spoofable X-9r-Real-Ip Header