GHSA-vc32-4gwf-77xp: SQL Injection
Summary An OTP-enabled authenticated user who cannot use the HTTP configuration mutation endpoints without a valid secure session can still mutate Nginx configuration through /mcp and /mcpmessage using only ordinary authentication.
Details The HTTP configuration mutation surface is explicitly grouped behind middleware.RequireSecureSession(). By contrast, the MCP endpoints are exposed with only middleware.AuthRequired(). The MCP server exposes configuration mutation tools including nginxconfigadd and nginxconfigmodify, so OTP-enabled users gain an alternate path around the intended step-up requirement.
Relevant code paths: - api/config/router.go - internal/middleware/securesession.go - mcp/router.go - mcp/config/configadd.go - mcp/config/configmodify.go
This is a security-control bypass rather than a missing feature. The product already established that OTP-enabled users should complete a secure session before high-impact configuration mutations are accepted on the HTTP path.
PoC I verified this locally in an isolated environment with a temporary end-to-end harness that exercised the real /mcp and /mcpmessage routes.
What the executed test did: 1. Created a temporary config directory and configured Nginx control commands to harmless local values (true) to avoid touching the host. 2. Created a real OTP-enabled user in a temporary SQLite database. 3. Generated a real JWT for that OTP-enabled user. 4. Started a local test server exposing the real /mcp and /mcpmessage routes. 5. Opened an authenticated SSE connection to /mcp with the JWT and no X-Secure-Session-ID. 6. Initialized the MCP session over /mcpmessage. 7. Called the real nginxconfigadd tool over /mcpmessage. 8. Verified that the tool succeeded and created mcp-bypass.conf in the managed config directory without any secure-session step-up.
Observed result from the actual local verification: - The MCP session initialized successfully without any X-Secure-Session-ID. - The config file was written through the MCP tool path using only JWT authentication.
Impact OTP-enabled accounts lose the intended step-up protection for high-impact Nginx configuration changes when MCP is enabled. A user who should be blocked until re-authenticating can still create or modify configuration files and trigger reload behavior through MCP.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
go/github.com/0xJacky/Nginx-UIto a version that resolves this vulnerability.Fixed in 1.9.10-0.20260703131214-23d1934099b0
Event History
Frequently Asked Questions
Which users are exposed to this bypass?
OTP-enabled authenticated users are affected when they can access the MCP endpoints. The issue allows those users to bypass the intended secure-session step-up requirement for configuration changes.
What does an attacker need to exploit the issue?
An attacker needs ordinary authentication to access /mcp or /mcp_message. A valid secure session is not required on those MCP routes.
What configuration changes can be made through the affected path?
The MCP server exposes configuration mutation tools including nginx_config_add and nginx_config_modify. These tools can be used to add or modify Nginx configuration through the alternate authenticated path.