CVE-2026-42221

CRITICAL EPSS 26.5%
Published May 4, 20261mo ago · Modified Jun 17, 20262w ago
9.8 CVSS 3.1
Critical
Find Similar
Published May 4, 2026 1mo ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
9.8
Exploitability
3.9
Impact
5.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
26.5% percentile
Exploit & Patch Status
Public Exploit Known
No Patch Available

Weaknesses 1

CWE-306 Missing Authentication for Critical Function Authentication

Affected Products 1

VendorProductVersionRange
nginxuinginx_ui*≥2.0.0  –  <2.3.8

References 2

  • github.com https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.8
    Release Notes
  • github.com https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp
    ExploitMitigationVendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.