What is 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.
The record classifies CVE-2026-33032 under weakness class CWE-306. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 212 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS (FIRST)
- 2.5% probability of exploitation in the next 30 days, higher than 84.4% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 10/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-03-30, last modified 2026-04-16
Is CVE-2026-33032 being exploited?
Weaponised exploit code for CVE-2026-33032 is publicly available. 5 public proof-of-concept repositories are tracked for this identifier. A ProjectDiscovery Nuclei detection template exists (http/cves/2026/CVE-2026-33032.yaml). It currently carries a trending score of 41 in the Threadlinqs vulnerability feed.
- keraattin/CVE-2026-33032 (github)
- Twinson333/cve-2026-33032-scanner (github)
- Shreda/CVE-2026-33032-nginx-ui-vuln-lab (github)
- Baba01hacker666/CVE-2026-33032 (github)
- trickest/cve (trickest)
Affected products and versions
- Nginxui: Nginx Ui
Affected software packages:
go:github.com/0xJacky/Nginx-UI
How to fix CVE-2026-33032
Vendor advisory: https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h6c2-x2m2-mwhf. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2026-33032
3 tracked threats in the Threadlinqs corpus reference CVE-2026-33032, either in the campaign’s CVE list or as an indicator on the campaign record.
- Internet-Wide Reconnaissance Scans Target MCP Servers and Claude/Cursor AI-Agent Credentials — MEDIUM · 2026-07-13
- Nginx UI Authentication Bypass via Unauthenticated MCP Endpoint (CVE-2026-33032) — CRITICAL · 2026-04-17
- CVE-2026-33032 (MCPwn): nginx-ui Middleware Bypass Enabling Unauthenticated Configuration Write and Full Web Server Takeover — CRITICAL · 2026-04-16
Sources
Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories, ProjectDiscovery Nuclei. Last verified by Threadlinqs on .