CVE catalog

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 CheckOrigin unconditionally returning true,

[CVE catalog]

Severity
Medium · CVSS 5.5CVSS: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
Published
Source
[NVD] · [CVE record]
EPSS
0.18% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

DistributionPackageReleaseVersionStatus
Cpenginx_uiNot reported2.3.5fixed
Cpenginx_uiNot reported2.3.5fixed

Fixed-version evidence

DistributionPackageTypeReleaseFixed versionUrgencyOriginBugs
Cpenginx_uicpeNot reported2.3.5Not reportedNot reportedNot reported
Cpenginx_uicpeNot reported2.3.5Not reportedNVD-CVE-2026-34403Not reported

OpenFactory catalog packages

No matching packages in this catalog.

Observed:

References

[CERT-Bund public advisories] · [FIRST EPSS] · [National Vulnerability Database (NVD)]