---
cve: "CVE-2026-84317"
severity: "HIGH"
cvss: 8.8
epss: "0.5%"
vendor: "0xJacky"
kev: false
exploited: false
published: "2026-10-12 21:17:22"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-11-09T18:29:27+01:00"
---

# CVE-2026-84317

> 8.8 HIGH · 🧪 PoC

## Beschreibung

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.

## CNA-Record (Kanon, cvelistV5)

- CNA: **GitHub_M**
- State: PUBLISHED
- Stand: 2026-10-13 17:50:15
- CNA-CVSS: **8.8** (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **poc**
  - Automatable: **no**
  - Technical Impact: **total**

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Schwachstellen-Klasse

- **CWE-20** — Improper Input Validation
  The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- **CWE-693** — Protection Mechanism Failure
  The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.

## Angriffsmuster (CAPEC)

- [CAPEC-10 — Buffer Overflow via Environment Variables](https://capec.mitre.org/data/definitions/10.html) _(Severity: High)_
- [CAPEC-13 — Subverting Environment Variable Values](https://capec.mitre.org/data/definitions/13.html) _(Severity: Very High)_
- [CAPEC-101 — Server Side Include (SSI) Injection](https://capec.mitre.org/data/definitions/101.html) _(Severity: High)_
- [CAPEC-104 — Cross Zone Scripting](https://capec.mitre.org/data/definitions/104.html) _(Severity: High)_
- [CAPEC-108 — Command Line Execution through SQL Injection](https://capec.mitre.org/data/definitions/108.html) _(Severity: Very High)_
- [CAPEC-109 — Object Relational Mapping Injection](https://capec.mitre.org/data/definitions/109.html) _(Severity: High)_
- [CAPEC-110 — SQL Injection through SOAP Parameter Tampering](https://capec.mitre.org/data/definitions/110.html) _(Severity: Very High)_
- [CAPEC-120 — Double Encoding](https://capec.mitre.org/data/definitions/120.html) _(Severity: Medium)_

## ATT&CK-Techniken

- [T1562.003 — Impair Defenses:Impair Command History Logging](https://attack.mitre.org/techniques/T1562/003/)
- [T1574.006 — Hijack Execution Flow:Dynamic Linker Hijacking](https://attack.mitre.org/techniques/T1574/006/)
- [T1574.007 — Hijack Execution Flow:Path Interception by PATH Environment ](https://attack.mitre.org/techniques/T1574/007/)

## Patch verfügbar (OSV)

- 0540f3ecf7824e9adbe408f3166d151651ccf4dd (Commit)
- 23d1934099b05b2a01589b48129dc3d3159d91c2 (Commit)

## BSI-Hinweise (deutsch)

- [nginx-ui: Mehrere Schwachstellen](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2026-2390) — _BSI-Einstufung: hoch_
  Ein Angreifer kann mehrere Schwachstellen in nginx-ui ausnutzen, um beliebigen Code auszuführen, einschließlich der Codeausführung mit Root-Rechten; erweiterte Rechte zu erlangen; eine Kontoübernahme durchzuführen; Sicherheitsmaßnahmen zu umgehen; oder Daten offenzulegen und zu manipulieren.

## Referenzen

- <https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-76pm-mq2q-9gcr>
- <https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2>
- <https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-84317/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_