Cyber Posture

CVE-2026-42222

High

Published: 04 May 2026

Published
04 May 2026
Modified
04 May 2026
KEV Added
Patch
CVSS Score 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0004 12.4th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Description

Nginx UI is a web user interface for the Nginx web server. In version 2.3.5, an unauthenticated bootstrap takeover exists in nginx-ui during the initial installation window exposed by POST /api/install. At time of publication no public patches are available.

Likely Mitigating ControlsAI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-284 CWE-306

Device lock enforces restricted access until re-authentication, directly reducing unauthorized use of active sessions.

addresses: CWE-284 CWE-306

Explicitly identifying and documenting actions permitted without identification or authentication enforces proper access control boundaries by defining justified exceptions.

addresses: CWE-284 CWE-306

Requiring authorization and configuration controls for mobile device connections directly enforces access control and prevents unauthorized devices from reaching organizational systems.

addresses: CWE-284 CWE-306

Provides a tamperproof, always-invoked, and verifiable mechanism to enforce access control policies.

addresses: CWE-284 CWE-306

Provides capability to review session content, directly detecting violations of access control.

addresses: CWE-284 CWE-306

Control assessments verify that access controls are implemented correctly and operating as intended, detecting improper access control before exploitation.

addresses: CWE-284 CWE-306

Certification requires independent assessment confirming access controls are implemented correctly and effective.

addresses: CWE-284 CWE-306

Restricting available functions and services reduces the attack surface and enforces proper access control boundaries.

Security SummaryAI

CVE-2026-42222 is an unauthenticated bootstrap takeover vulnerability in Nginx UI version 2.3.5, a web user interface for the Nginx web server. The issue arises during the initial installation window and is exposed through the POST /api/install endpoint, enabling improper access control as classified under CWE-284 (Improper Access Control) and CWE-306 (Missing Authentication for Critical Function). The vulnerability carries a CVSS v3.1 base score of 8.1 (AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating high severity due to its potential for significant impact.

Remote attackers with network access can exploit this vulnerability without requiring user privileges or interaction, though it demands high attack complexity. Exploitation allows attackers to hijack the bootstrap process during initial setup, achieving high confidentiality, integrity, and availability impacts, effectively compromising the Nginx UI instance.

The GitHub security advisory (GHSA-mxqh-q9h6-v8pq) confirms that, at the time of publication on 2026-05-04, no public patches are available for this vulnerability.

Details

CWE(s)

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Why these techniques?

Unauthenticated remote exploitation of the public-facing Nginx UI /api/install endpoint during bootstrap directly enables initial access via T1190 Exploit Public-Facing Application.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

References