CVE-2026-42221

8.1 HIGH
Published: May 04, 2026 Modified: May 06, 2026
View on NVD

Description

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.8
Source: security-advisories@github.com
Release Notes
https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp
Source: security-advisories@github.com
Exploit Mitigation Vendor Advisory
https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Exploit Mitigation Vendor Advisory

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
8.1 / 10.0
EPSS (Exploit Probability)
0.3%
26th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

nginxui