CVE-2026-84318 · GHSA-9jww-cxg5-rj9m
Nginx UI: MCP `nginx_config_add` Bypasses Directive Validation — Authenticated RCE
- Risk score
- 73/100
- CVSS
- 8.8 v3.1
- Exploit chance (30 days)
- 0.6%
- Published
- 12 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- Nginx UI is a web user interface for the Nginx web server. From 2.0.0-rc.6 until 2.4.1, the MCP tool nginx_config_add writes nginx configuration files to disk and triggers an nginx reload without calling config.ValidateConfigFile. The identical flow in the REST API (POST /api/configs) does call that function and corre…
- Affected
- github.com/0xJacky/Nginx-UI (go) >= 1.9.10-0.20250506154222-1330888280a2, < 1.9.10-0.20260703131214-23d1934099b0
- Fix
- Upgrade github.com/0xJacky/Nginx-UI to 1.9.10-0.20260703131214-23d1934099b0 or later.
- Exploitation
- No known exploitation
Story map
At a glance
github.com/0xJacky/Nginx-UI: Amber, patch this week. Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, config.ValidateConfigDirectives splits configuration by newline and checks only the first directive token on each line even though Nginx permits multiple semicolon-separated directives on one line. An authenticated caller can place a benign dir…
The flaws
- CVE-2026-84318: Nginx UI: MCP `nginx_config_add` Bypasses Directive Validation — Authenticated RCE (CVSS 8.8 · EPSS 1%)
- CVE-2026-84316: Nginx UI: nginx config directive denylist (ValidateConfigFile) is bypassable via same-line ";" separation → authenticated directive injection (RCE on the official image) (CVSS 8.8 · EPSS 0%)
- CVE-2026-84317: Nginx UI: MCP nginx_config_add skips config directive validation → authenticated nginx directive injection (RCE on the official image) (CVSS 8.8 · EPSS 0%)
- CVE-2026-84314: Nginx UI: Account Takeover via Missing `RequireSecureSession` on User Management Endpoint (CVSS 8.7 · EPSS 0%)
The fix
Upgrade github.com/0xJacky/Nginx-UI: 2.4.1 or later on your release line
Who is exposed: github.com/0xJacky/Nginx-UI (go) < 1.9.10-0.20260703131214-23d1934099b0
Where it stands
- Public proof of concept
Connects to
- Same weakness: CWE-693 (CWE-693). 59 other warnings in 30 days
Why it is Amber
- CVSS 8.8 high
- On your watchlist: nginx, Go
Affected packages
| Package | Ecosystem | Vulnerable | Fixed in |
|---|---|---|---|
| github.com/0xJacky/Nginx-UI | go | >= 1.9.10-0.20250506154222-1330888280a2, < 1.9.10-0.20260703131214-23d1934099b0 | 1.9.10-0.20260703131214-23d1934099b0 |
References
- https://github.com/advisories/GHSA-9jww-cxg5-rj9m
- https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-9jww-cxg5-rj9m
- https://nvd.nist.gov/vuln/detail/CVE-2026-84318
- https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2
- https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1
- https://github.com/advisories/GHSA-9jww-cxg5-rj9m
Original description
Nginx UI is a web user interface for the Nginx web server. From 2.0.0-rc.6 until 2.4.1, the MCP tool nginx_config_add writes nginx configuration files to disk and triggers an nginx reload without calling config.ValidateConfigFile. The identical flow in the REST API (POST /api/configs) does call that function and correctly rejects dangerous directives. An authenticated attacker can exploit this gap to write config files containing any blocked directive (perl, js_import, load_module, user root, etc.), bypassing nginx-ui's entire security layer. On a server with the nginx Perl, njs, or Lua module loaded, this is post-authentication Remote Code Execution. This issue is fixed in version 2.4.1.
Last activity 12 Oct 2026. Patch Forecast updates every hour.