---
id: CVE-2026-56679
aliases:
  - GHSA-vmjq-hvgq-2wv4
title: >-
  9router: Mass assignment in PATCH /api/settings allows authenticated
  authorization downgrade
summary: >-
  9router: Mass assignment in PATCH /api/settings allows authenticated
  authorization downgrade
severity: high
cwe:
  - CWE-915
vendor: 9router
product: 9router
ecosystem: npm
affected:
  - 9router <= 0.5.2
patched:
  - 9router 0.5.4
published: '2026-09-23'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T18:12:34Z'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-vmjq-hvgq-2wv4'
references:
  - url: 'https://github.com/decolua/9router/security/advisories/GHSA-vmjq-hvgq-2wv4'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56679'
  - url: 'https://github.com/advisories/GHSA-vmjq-hvgq-2wv4'
tags:
  - ghsa
  - npm
epss: 0.00519
epssPercentile: 0.41574
ingestedAt: '2026-09-23T18:29:33.151Z'
---

## Overview

### Summary
The `PATCH /api/settings` endpoint writes the entire request body to persistent settings without a field whitelist. An authenticated user can set security-critical fields that are not meant to be modifiable here — notably `requireLogin`. Setting `requireLogin: false` disables authentication for the whole application, exposing all protected routes (e.g. `/api/keys`, `/api/providers`) to unauthenticated access.

### Details
Root cause is unfiltered mass assignment (CWE-915):

- `src/app/api/settings/route.js` (PATCH handler) parses the body and passes it to `updateSettings(body)`, with special handling only for `newPassword` and `oidcClientSecret`. All other fields pass through.
- `src/lib/db/repos/settingsRepo.js` — `updateSettings` does `next = { ...current, ...updates }`, so any key in the body overwrites stored settings, including `requireLogin`, `tunnelDashboardAccess`, `authMode`.
- `src/dashboardGuard.js` — `isAuthenticated` returns `true` whenever `settings.requireLogin === false`, bypassing auth on all protected routes.

This is distinct from CVE-2026-5842 (CWE-285, pre-auth bypass on `/api`, patched in 0.3.75). This finding requires a valid authenticated session and abuses input handling, not missing authentication.

### PoC
Instance on `localhost:20128`, default password `123456`.

1. Authenticate, capture session:
   `POST /api/auth/login` body `{"password":"123456"}` → `200 {"success":true}`
2. Mass-assign with the authenticated session:
   `PATCH /api/settings` body `{"requireLogin":false}` → `200`, response confirms `"requireLogin":false`
3. Verify bypass with NO session/credentials:
   `GET /api/keys` → `200`, returns full API key list unauthenticated
4. Cleanup (authenticated): `PATCH /api/settings` body `{"requireLogin":true}` → `GET /api/keys` returns `401` again

### Impact
Post-authentication mass assignment. Any authenticated user (including one using the default password) can disable authentication globally, then read all stored API keys and provider connection data without credentials, and toggle tunnel/dashboard exposure. Escalates to remote full compromise when chained with the default password `123456` on an instance exposed via tunnel (`tunnelDashboardAccess` defaults to `true`).

### Suggested fix
Whitelist user-configurable fields in the PATCH handler; move security-critical fields (`requireLogin`, `tunnelDashboardAccess`, `authMode`) to a dedicated endpoint requiring re-authentication (current-password re-entry), mirroring the existing DB export/import re-auth flow.

## Affected packages

- `9router <= 0.5.2`

## Remediation

Upgrade to a patched release:

- `9router 0.5.4`