CVE-2026-27944
Nginx UI: Unauthenticated Backup Download with Encryption Key Disclosure
- Published
- Mar 5, 2026
- Updated
- Mar 19, 2026
- Assigning CNA
- GitHub_M
- Evidence observed
- Aug 8, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HModerate · next 30 days
- Percentile
- 97.6%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
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.
Sources
7Proof-of-concept exploit for CVE-2026-27944, demonstrating decryption of nginx-ui backups via exposed private key endpoint, for authorized security testing.
- HTB-Snapped-WriteupResearch
HTB Snapped — Hard Linux machine writeup. CVE-2026-27944 (Nginx UI unauthenticated backup disclosure) chained with CVE-2026-3888 (snapd race condition LPE) to achieve full system compromise.
Responsible use
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