Auth bypass in 0xjacky Nginx-Ui
CVE-2026-33032
Nginx UI is a web user interface for the Nginx web server. In versions 2.3.5 and prior, the nginx-ui MCP (Model Context Protocol) integration exposes two HTTP endpoints: /mcp and /mcp_message. While /mcp requires both IP whitelisting and authentication (AuthRequired() middleware), the /mcp_message endpoint only applies IP whitelisting - and the default IP whitelist is empty, which the middleware treats as "allow all". This means any network attacker can invoke all MCP tools without authentication, including restarting nginx, creating/modifying/deleting nginx configuration files, and triggering automatic config reloads - achieving complete nginx service takeover. At time of publication, there are no publicly available patches.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.025 (84.2th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 84th percentile — 84.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.363 · newest: 0.025 · change: -0.338
Affected products
- 0xjacky Nginx-Ui — versions <= 2.3.5
- Nginxui nginx Ui
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/0xJacky/nginx-ui/security/advisories/GHSA-h6c2-x2m2-mwhf (Exploit, Mitigation, Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2026-33032?
- CVE-2026-33032 is a critical-severity vulnerability in 0xjacky Nginx-Ui, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2026-03-30.
- How severe is CVE-2026-33032?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-33032 known to be exploited?
- 4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.