Missing Authentication for Critical Function in nginx-ui - CVE-2026-33032
Published: April 16, 2026
Vulnerability identifier: #VU126309
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Amber
CVE-ID: CVE-2026-33032
CWE-ID: CWE-306
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vendor: Nginx UI
Affected software:
nginx-ui
nginx-ui
Detailed vulnerability description
The vulnerability allows a remote attacker to take control of the nginx service, disclose sensitive configuration information, and cause a denial of service.
The vulnerability exists due to missing authentication for critical functionality in the /mcp_message endpoint when handling MCP tool invocation requests. A remote attacker can send specially crafted HTTP requests to invoke MCP tools without authentication to take control of the nginx service, disclose sensitive configuration information, and cause a denial of service.
The issue occurs because /mcp_message routes to the same MCP handler as /mcp, while the default empty IP whitelist is treated as allow-all.
How to mitigate CVE-2026-33032
Install security update from vendor's website.