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 3.1
- 9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS
- 1.3% chance of exploitation in the next 30 days; higher than 71% of CVEs (scores of 2026-10-26)
- CWE
- CWE-306
- Published
- Modified
- Record from
- the NVD, synced
Affected
- nginxui:nginx_ui
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-h27v-ph7w-m9fp | Go | github.com/0xJacky/Nginx-UI | >=2.0.0 <2.3.8 | 2.3.8 |
| GO-2026-5412 | Go | github.com/0xJacky/Nginx-UI | all versions | no fix published |