Dashboard / CVE-2026-42221

CVE-2026-42221

CRITICAL
INFO Priority: 0.13 BB Relevance: 80/100
Published: 2026-05-04 Modified: 2026-10-26 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction Conf. Impact Integ. Impact

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: None
S: Unchanged
C: High
I: High
A: High

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.

Weakness Classification (1)

Affected Software (1)

VendorProductVersion
nginxui nginx_ui 2.0.0 – 2.3.8

References & Advisories (2)

Bug Bounty Relevance

80 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction

CVSS Score

9.8 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploitation Probability

1.34%
Raw Score 0.013420
Percentile 71.3%
Date 2026-10-29

EPSS Trend

2026-10-29
0.01342
2026-10-28
0.01342

Intelligence Sources

nvd ref →

External Links