CVE-2026-34403
Nginx UI is a web user interface for the Nginx web server. Prior to version 2.3.5, 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. Version 2.3.5 patches the issue.
- Affected products
- Nginx-Ui
- Nginxui Nginx Ui
- < 2.3.5
- Fix
- Available
- CVSS 3.1
- 8.1 HIGH
- EPSS
- 0.2% (7th percentile)
- Weakness
- CWE-1385
- NVD status
- Analyzed
- Published
- 2026-04-20
No indexed exploits for CVE-2026-34403 yet
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