Missing Authentication for Critical Function in nginx-ui - CVE-2026-27944
Published: April 23, 2026 / Updated: May 15, 2026
Vulnerability identifier: #VU127228
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Amber
CVE-ID: CVE-2026-27944
CWE-ID: CWE-306
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vendor: Nginx UI
Affected software:
nginx-ui
nginx-ui
Detailed vulnerability description
The vulnerability allows a remote attacker to download and decrypt a full system backup containing sensitive information.
The vulnerability exists due to missing authentication for critical function in the /api/backup endpoint when handling unauthenticated backup requests. A remote attacker can send a crafted GET request to download and decrypt a full system backup containing sensitive information.
The AES-256 key and IV are disclosed in the X-Backup-Security response header, and the backup may contain user credentials, session tokens, SSL private keys, and nginx configuration data.
How to mitigate CVE-2026-27944
Install security update from vendor's website.