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CVE-2026-84318— Nginx UI: MCP `nginx_config_add` Bypasses Directive Validation — Authenticated RCE

Quick assessment

Affected
0xJacky nginx-ui
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Nginx UI 是 Nginx Web 服务器的一个 Web 用户界面。从版本 2.0.0-rc.6 到 2.4.1，MCP 工具 在将 Nginx 配置文件写入磁盘并触发 Nginx 重新加载之前，未调用 函数进行配置验证。而在 REST API（POST /api/configs）中相同的流程会调用该验证函数，并正确拒绝存在风险的安全指令。攻击者在成功认证后，可利用此安全漏洞写入包含任何被禁止指令（如 perl、js_import、load_module、user root 等）的配置文件，从而绕过 Ngin

CVSS 8.8 · High EPSS 0.62% · P48

Affected Version Matrix 1

VendorProduct Version RangeStatus
0xJacky nginx-ui >= 2.0.0-rc.6, < 2.4.1 affected
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I. Basic Information for CVE-2026-84318

Vulnerability Information
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Vulnerability Title
Nginx UI: MCP `nginx_config_add` Bypasses Directive Validation — Authenticated RCE
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
保护机制失效
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
0xJacky nginx-ui >= 2.0.0-rc.6, < 2.4.1 -

II. Public POCs for CVE-2026-84318

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III. Intelligence Information for CVE-2026-84318

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Vendor Advisories for CVE-2026-84318 (1)

Same Patch Batch · 0xJacky · 2026-10-12 · 11 CVEs total

CVE-2026-84313 8.8 HIGH Nginx UI: TOTP / passkey enrolment requires no re-authentication, enabling persistent acco
CVE-2026-84316 8.8 HIGH Nginx UI: nginx config directive denylist (ValidateConfigFile) is bypassable via same-line
CVE-2026-84317 8.8 HIGH Nginx UI: MCP nginx_config_add skips config directive validation → authenticated nginx dir
CVE-2026-84314 8.7 HIGH Nginx UI: Account Takeover via Missing `RequireSecureSession` on User Management Endpoint
CVE-2026-84315 8.3 HIGH Nginx UI OTP secure-session step-up is missing on sensitive mutation routes
CVE-2026-84319 8.3 HIGH Nginx UI: MCP configuration tools bypass restricted directive validation and allow seconda
CVE-2026-84360 8.1 HIGH Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools
CVE-2026-84312 7.1 HIGH Nginx UI: Casdoor SSO callback uses a constant `state` parameter (login CSRF)
CVE-2026-84320 6.3 MEDIUM Nginx UI: Auto backup name allows path traversal outside validated storage path
CVE-2026-84321 5.4 MEDIUM Nginx UI: Standalone short tokens survive administrative revocation in cache and authentic

IV. Related Vulnerabilities

Same product: nginx-ui
Same vendor: 0xJacky
Same weakness: CWE-693

V. Comments for CVE-2026-84318

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