{"id":"CVE-2026-84318","published":"2026-10-12T21:17:22.360","lastModified":"2026-10-13T15:17:50.383","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.","cvssScore":8.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwes":["CWE-693"],"vendors":[],"products":[],"references":[{"url":"https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2","tags":[]},{"url":"https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1","tags":[]},{"url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-9jww-cxg5-rj9m","tags":[]},{"url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-9jww-cxg5-rj9m","tags":[]}],"exploitRefs":[{"url":"https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2","tags":[]},{"url":"https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1","tags":[]},{"url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-9jww-cxg5-rj9m","tags":[]},{"url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-9jww-cxg5-rj9m","tags":[]}],"hasPoc":true,"ai":{"summary":"Nginx UI allows authenticated attackers to bypass security controls and write dangerous nginx configuration directives that would normally be blocked, leading to potential remote code execution when nginx modules like Perl, njs, or Lua are installed.","exploitability":"Exploitation requires an authenticated user account with access to the MCP tool nginx_config_add functionality, which is relatively easy to achieve in environments where Nginx UI is deployed.","blast_radius":"The impact could be significant across all servers running vulnerable Nginx UI versions that have nginx modules loaded, potentially allowing attackers to execute arbitrary code on the host system.","remediation":"Upgrade to version 2.4.1 or later to fix the configuration validation gap in the MCP tool.","detection":"Monitor for unusual file writes to nginx configuration directories by user accounts with MCP access, particularly when followed by nginx reload processes.","tags":["rce","config-bypass","web","nginx"],"model":"garnet-coder","analyzedAt":"2026-10-16T09:02:03.431Z"}}