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CVE-2026-34403

Nginx-UI vulnerable to Cross-Site WebSocket Hijacking (CSWSH) via missing origin validation on all WebSocket endpoints

Published: Apr 20, 2026Updated: Apr 22, 2026 Sources: CVE List NVD BDUCWE-1385
8.1HIGH
NVD MITRE
EPSS Score
0.2%
Top 92.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:RS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-1385

Affected Products

nginx uinginxui
On-prem
Networking Infrastructure / network-management
nginx-ui0xJacky
Mixed
Cloud & SaaS / saas-application
Nginx UIСообщество свободного программного обеспечения
On-prem
Web & CMS Plugins
nginxuicommercialNetworking Infrastructureaka nginx ui, nginxui
0xjackyindividual-devCloud & SaaSaka nginx-ui
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf

Exploitability

Official Patch Available
Workaround Available
No detection template yetWe can run the check for you — a free external exposure review, no install. Check my exposure

References

https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.5
github.com
https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-78mf-482w-62qj
github.com

Timeline

Published
Apr 20, 2026
Last Updated
Apr 22, 2026

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