nginx-ui: Unauthenticated first-boot instance claim via POST /api/install allows remote bootstrap takeover

published 2026-05-04 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-27137 , GHSA-mxqh-q9h6-v8pq , GO-2026-5521

cvss: 8.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 27%
public exploits: 0; none known

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.

Patch / fix

distros 1

govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 6 mo ago (2026-05-06)

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-mxqh-q9h6-v8pq referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub	3.1	8.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
go	github.com/0xJacky/nginx-ui	1 listed version all versions	no fix listed

Affected products

0xJacky nginx-ui

Classification

Weakness

CWE-306 Missing Authentication for Critical Functionality
CWE-284 Improper Access Control

References

github.com /0xJacky/nginx-ui/security/advisories/GHSA-mxqh-q9h6-v8pq
exploit, web, vendor-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2026-42222
advisory
github.com /0xJacky/nginx-ui
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary