CVE-2026-34403: 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…

PriorityP343high8.1CVSS 3.1

AVNACLPRNUIRSUCHIHAN

EPSS

0.18%

7.3th percentile

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.

Affected

3 ranges

Vendor	Product	Version range	Fixed in
0xjacky	nginx-ui	< 2.3.5	2.3.5
github.com	0xjacky_nginx-ui	>= 0 < 1.9.10-0.20260316053337-1a9cd29a3082	1.9.10-0.20260316053337-1a9cd29a3082
nginxui	nginx_ui	< 2.3.5	2.3.5

CVSS provenance

nvdv3.18.1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

nvdv4.05.5MEDIUMCVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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