---
title: "CVE-2026-27944: Nginx-UI Vulnerable to Unauthenticated Backup Download with Encryption Key Disclosure"
url: https://erroneo.us/security/cve/CVE-2026-27944/
description: "CVE-2026-27944 (github.com/0xJacky/Nginx-UI (Go)): Nginx UI is a web user interface for the Nginx web server. Prior to version 2.3.3, the /api/backup…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-03-05
date_modified: 2026-03-19
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-27944"
kev: false
cvss: 9.8
epss: 0.01014
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-27944: Nginx-UI Vulnerable to Unauthenticated Backup Download with Encryption Key Disclosure

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 1.0% , percentile 63: FIRST’s model estimates a 1.0% chance of exploitation activity in the next 30 days, higher than 63% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes github.com/0xJacky/Nginx-UI (Go) < 2.3.3, fixed in 2.3.3 . Check your lockfile, including transitive dependencies.

## What it is

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.

## Affected packages

- Go `github.com/0xJacky/Nginx-UI` < 2.3.3 → fixed: 2.3.3

## Affected products (CVE record)

- 0xJacky nginx-ui: < 2.3.3

## Severity

- GitHub_M CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.01% probability of exploitation activity in the next 30 days; percentile 63.

## Sources

- [GitHub Advisory GHSA-g9w5-qffc-6762](https://github.com/advisories/GHSA-g9w5-qffc-6762)
- [CVE.org record CVE-2026-27944](https://www.cve.org/CVERecord?id=CVE-2026-27944)
- [NVD entry CVE-2026-27944](https://nvd.nist.gov/vuln/detail/CVE-2026-27944)
- [github.com](https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-g9w5-qffc-6762)
- [csrc.nist.gov](https://csrc.nist.gov/publications/detail/sp/800-57-part-1/rev-5/final)
- [owasp.org](https://owasp.org/www-project-top-ten/2017/A2_2017-Broken_Authentication)
- [owasp.org](https://owasp.org/www-project-top-ten/2017/A3_2017-Sensitive_Data_Exposure)

---
Source page: https://erroneo.us/security/cve/CVE-2026-27944/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt