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CVE-2026-84317— Nginx UI: MCP nginx_config_add skips config directive validation → authenticated nginx directive injection (RCE on the official image)

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。在版本 2.4.1 之前， 文件中的 函数充当安全控制机制，用于阻止危险的 Nginx 指令（如 、 、 ，涉及 njs/Perl 模块以及 ）。该控制机制在四个配置写入路径中的三个上被强制执行： 、 和 。然而，第四个路径——即 MCP 工具 （位于 ）——并未调用此验证函数，而是直接将调用方提供的内容写入磁盘并重新加载 Nginx。因此，经过身份验证的 MCP 调用者（或通过提示注入诱发的 MCP 代理）可以注入该安全控制本应阻止的精确指

CVSS 8.8 · High EPSS 0.38% · P30

Affected Version Matrix 1

VendorProduct Version RangeStatus
0xJacky nginx-ui < 2.4.1 affected
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I. Basic Information for CVE-2026-84317

Vulnerability Information
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Vulnerability Title
Nginx UI: MCP nginx_config_add skips config directive validation → authenticated nginx directive injection (RCE on the official image)
Source: CVE Program / CVE List V5
Vulnerability Description
Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, internal/config/validation.go (ValidateConfigFile) is a security control that blocks dangerous nginx directives — js_*, perl_*, load_module of the njs/perl modules, and user root. It is enforced on three of the four config-write paths: api/config/add.go, api/config/modify.go, and mcp/config/config_modify.go. The fourth path — the MCP tool nginx_config_add (mcp/config/config_add.go) — does NOT call it: it writes the caller-supplied content straight to disk and reloads nginx. An authenticated MCP caller (or an MCP agent induced via prompt injection) can therefore inject exactly the directives the control is meant to block, leading to nginx code execution on deployments where the njs/perl module is available (e.g. the official Docker image). 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
输入验证不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
0xJacky nginx-ui < 2.4.1 -

II. Public POCs for CVE-2026-84317

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III. Intelligence Information for CVE-2026-84317

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Vendor Advisories for CVE-2026-84317 (1)

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

CVE-2026-84318 8.8 HIGH Nginx UI: MCP `nginx_config_add` Bypasses Directive Validation — Authenticated RCE
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-2026-84314 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-20

V. Comments for CVE-2026-84317

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