CVE-2026-84318
Nginx UI: MCP `nginx_config_add` Bypasses Directive Validation — Authenticated RCE
At a glance
- Source
- NVD
- EPSS
- EPSS 0.82 % · percentile 57 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Deferred
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.
Weaknesses (CWE)
- CWE-693 — Protection Mechanism Failure
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | GitHub_M |
| CVSS 3.1 | HIGH 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | NVD · security-advisories@github.com (Secondary) |
Advisories
- GHSA-9jww-cxg5-rj9m — Nginx UI: MCP `nginx_config_add` Bypasses Directive Validation — Authenticated RCE
- GO-2026-6781 — Nginx UI: MCP `nginx_config_add` Bypasses Directive Validation — Authenticated RCE in github.com/0xJacky/Nginx-UI
European references
- ENISA EUVD · EUVD-2026-97908
- GCVE · GCVE-0-2026-84318
Affected products
| Product | Versions |
|---|---|
| 0xJacky · nginx-ui | affected >= 2.0.0-rc.6, < 2.4.1 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |