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Fencer Intel
critical 9.8

CVE-2026-27944 in the critical feed json

Nginx UI: Unauthenticated Backup Download with Encryption Key Disclosure

published 8mo ago modified 4mo ago also EUVD-2026-9847 , GHSA-g9w5-qffc-6762 , GO-2026-4614

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
22.8%
EPSS 22.8% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known, plus a Nuclei check

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.

Patch / fix

  • go github.com/0xJacky/Nginx-UI 2.3.3
  • nginxui nginx_ui 2.3.3
  • govulncheck-vulndb openSUSE Leap 15.6 0.0.20260317T205859-150000.1.152.1

suse advisories SUSE-SU-2026:1042-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

Is CVE-2026-27944 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
7mo ago

Exploit prediction

22.84% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • Nuclei template Nginx UI < 2.3.3 - Information Disclosure nuclei detection template
  • github.com https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-g9w5-qffc-6762 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 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
<2.3.3
all versions
2.3.3

Affected products

  • 0xJacky nginx-ui

Classification

Weakness
  • CWE-311 Missing Encryption of Sensitive Data
  • CWE-306 Missing Authentication for Critical Functionality

References

Sources

Fencer Intel 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.