CVE-2026-42221

Nginx UI is a web user interface for the Nginx web server. From version 2.0.0 to before version 2.3.8, an unauthenticated network attacker can claim the initial administrator account on a fresh nginx-ui instance during the first-run setup window. The public /api/install endpoint is reachable without authentication, and the request-encryption flow only protects payload confidentiality in transit; it does not authenticate who is allowed to perform installation. A remote attacker who reaches the service before the legitimate operator can set the admin email, username, and password, causing permanent initial-instance takeover. This issue has been patched in version 2.3.8.

CVSS v3 8.1 HIGH

8.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.2 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.8	Release Notes
https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp	Exploit Mitigation Vendor Advisory
https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp	Exploit Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:nginxui:nginx_ui:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-05-04 21:16

Updated : 2026-06-17 10:47

NVD link : CVE-2026-42221

Mitre link : CVE-2026-42221

CVE.ORG link : CVE-2026-42221

JSON object : View

Products Affected

nginxui

nginx_ui

CWE

CWE-306

Missing Authentication for Critical Function

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