CVE-2026-34403

April 21, 2026, 4:20 p.m.

5.5
Medium

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.

Product(s) Impacted

Vendor Product Versions
Nginx
  • Nginx Ui
  • <2.3.5

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-1385
Missing Origin Validation in WebSockets
The product uses a WebSocket, but it does not properly verify that the source of data or communication is valid.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
a nginx nginx_ui <2.3.5 / / / / / / /

References

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

Tags

[email protected]
CWE-1385
2026-04-20
CVE-2026-34403

CVSS Score

5.5 / 10

CVSS Data - 4.0

  • Attack Vector: NETWORK
  • Attack Complexity: LOW
  • Attack Requirements: NONE
  • Privileges Required: NONE
  • User Interaction: ACTIVE
  • Scope:
  • Confidentiality Impact: NONE
  • Integrity Impact: HIGH
  • Availability Impact: NONE
  • Exploit Maturity: PROOF_OF_CONCEPT

    • 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/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

    View Vector String

Timeline

Published: April 20, 2026, 9:16 p.m.
Last Modified: April 21, 2026, 4:20 p.m.

Status : Undergoing Analysis

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.