{"id":"CVE-2026-84318","state":"PUBLISHED","title":"Nginx UI: MCP `nginx_config_add` Bypasses Directive Validation — Authenticated RCE","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.","publishedAt":"2026-10-12T20:20:18.595Z","updatedAt":"2026-10-13T14:59:04.180Z","severity":{"score":8.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["0xJacky nginx-ui"],"affected":[{"vendor":"0xJacky","product":"nginx-ui","versions":[{"version":">= 2.0.0-rc.6, < 2.4.1","status":"affected"}]}],"references":["https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-9jww-cxg5-rj9m","https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2","https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1"],"weaknesses":["CWE-693"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/84xxx/CVE-2026-84318.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-84318","state":"PUBLISHED","datePublished":"2026-10-12T20:20:18.595Z","dateUpdated":"2026-10-13T14:59:04.180Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-09-01T16:17:43.079Z"},"containers":{"cna":{"title":"Nginx UI: MCP `nginx_config_add` Bypasses Directive Validation — Authenticated RCE","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"0xJacky","product":"nginx-ui","versions":[{"version":">= 2.0.0-rc.6, < 2.4.1","status":"affected"}]}],"references":[{"url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-9jww-cxg5-rj9m","name":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-9jww-cxg5-rj9m","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2","name":"https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2","tags":["x_refsource_MISC"]},{"url":"https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1","name":"https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.8,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-693","lang":"en","description":"CWE-693: Protection Mechanism Failure","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-12T20:20:18.595Z"},"source":{"advisory":"GHSA-9jww-cxg5-rj9m","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-9jww-cxg5-rj9m","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-13T14:58:57.805122Z","id":"CVE-2026-84318","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-13T14:59:04.180Z"}}]}}}