Auth bypass in 0xjacky Nginx-Ui
CVE-2026-27944
Nginx UI is a web user interface for the Nginx web server. Prior to version 2.3.3, the /api/backup endpoint is accessible without authentication and discloses the encryption keys required to decrypt the backup in the X-Backup-Security response header. This allows an unauthenticated attacker to download a full system backup containing sensitive data (user credentials, session tokens, SSL private keys, Nginx configurations) and decrypt it immediately. This issue has been patched in version 2.3.3.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.010 (61.8th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 62nd percentile — 61.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.222 · newest: 0.010 · change: -0.211
Affected products
- 0xjacky Nginx-Ui — versions < 2.3.3
- Nginxui nginx Ui
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/0xJacky/nginx-ui/security/advisories/GHSA-g9w5-qffc-6762 (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-27944?
- CVE-2026-27944 is a critical-severity vulnerability in 0xjacky Nginx-Ui, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2026-03-05.
- How severe is CVE-2026-27944?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-27944 known to be exploited?
- 8 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.