Nginx-UI vulnerable to Cross-Site WebSocket Hijacking (CSWSH) via missing origin validation on all WebSocket endpoints
Exact source revision recorded 23 Oct 2026 15:48:27 UTC. It does not establish the source's current position. Latest evidence.
cve-program · CVE-2026-34403
PublishedNginx 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.
- Source published
- 20 Apr 2026 20:16:47 UTC
- Source modified
- 21 Apr 2026 13:36:46 UTC
- Observed here
- 23 Oct 2026 15:48:27 UTC
- Source terms
- CVE Program Terms of Use
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CVSS 4.0 · 5.5 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