Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nginxui | Nginx Ui | < 2.3.5 |
Related Weaknesses (CWE)
References
- https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.5ProductRelease Notes
- https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-78mf-482w-62qjExploitMitigationVendor Advisory
FAQ
What is CVE-2026-34403?
CVE-2026-34403 is a vulnerability with a CVSS score of 8.1 (HIGH). 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,...
How severe is CVE-2026-34403?
CVE-2026-34403 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-34403?
Check the references section above for vendor advisories and patch information. Affected products include: Nginxui Nginx Ui.