CVE-2026-34403 (GCVE-0-2026-34403)

Vulnerability from cvelistv5 – Published: 2026-04-20 20:16 – Updated: 2026-04-21 13:36
VLAI
Title
Nginx-UI vulnerable to Cross-Site WebSocket Hijacking (CSWSH) via missing origin validation on all WebSocket endpoints
Summary
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.
Severity
5.5 (Medium)
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
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-21 13:36 UTC
CWE
  • CWE-1385 - Missing Origin Validation in WebSockets
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7926 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
0xJacky nginx-ui Affected: < 2.3.5
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

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