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.
History

Mon, 20 Apr 2026 22:45:00 +0000

Type Values Removed Values Added
First Time appeared 0xjacky
0xjacky nginx-ui
Vendors & Products 0xjacky
0xjacky nginx-ui

Mon, 20 Apr 2026 21:00:00 +0000

Type Values Removed Values Added
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.
Title Nginx-UI vulnerable to Cross-Site WebSocket Hijacking (CSWSH) via missing origin validation on all WebSocket endpoints
Weaknesses CWE-1385
References
Metrics cvssV4_0

{'score': 5.5, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-04-20T20:16:47.597Z

Reserved: 2026-03-27T13:45:29.620Z

Link: CVE-2026-34403

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-04-20T21:16:36.267

Modified: 2026-04-20T21:16:36.267

Link: CVE-2026-34403

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-04-20T22:30:19Z