CVE-2026-84319

Nginx UI: MCP configuration tools bypass restricted directive validation and allow secondary authenticated users to execute NJS in Nginx worker context

Description

Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, the regular HTTP configuration API rejects restricted Nginx directives such as load_module, js_import, and js_content. However, the MCP configuration interface allows a secondary authenticated user to write and apply equivalent restricted configuration content. This allows the user to load ngx_http_js_module.so, import attacker-controlled JavaScript, reload Nginx, and execute NJS in the Nginx worker context. This issue is fixed in version 2.4.1.

Scores

Weaknesses (CWE)

• CWE-693

Advisories

• GHSA-5r62-gj48-897x — Nginx UI: MCP configuration tools bypass restricted directive validation and allow secondary authenticated users to execute NJS in Nginx worker context
• GO-2026-6774 — Nginx UI: MCP configuration tools bypass restricted directive validation and allow secondary authenticated users to execute NJS in Nginx worker context in github.com/0xJacky/Nginx-UI

European references

• ENISA EUVD · EUVD-2026-97905
• GCVE · GCVE-0-2026-84319

Affected products

References

• https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-5r62-gj48-897x
• https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2
• https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1

Sources