{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-42221","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-04-25T05:04:37.029Z","datePublished":"2026-05-04T20:09:37.308Z","dateUpdated":"2026-05-05T14:14:11.906Z"},"containers":{"cna":{"title":"nginx-ui: Unauthenticated First-Run Installer Allows Remote Initial Admin Claim","problemTypes":[{"descriptions":[{"cweId":"CWE-306","lang":"en","description":"CWE-306: Missing Authentication for Critical Function","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"name":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp","tags":["x_refsource_CONFIRM"],"url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp"},{"name":"https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.8","tags":["x_refsource_MISC"],"url":"https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.8"}],"affected":[{"vendor":"0xJacky","product":"nginx-ui","versions":[{"version":">= 2.0.0, < 2.3.8","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-05-04T20:09:37.308Z"},"descriptions":[{"lang":"en","value":"Nginx UI is a web user interface for the Nginx web server. From version 2.0.0 to before version 2.3.8, an unauthenticated network attacker can claim the initial administrator account on a fresh nginx-ui instance during the first-run setup window. The public /api/install endpoint is reachable without authentication, and the request-encryption flow only protects payload confidentiality in transit; it does not authenticate who is allowed to perform installation. A remote attacker who reaches the service before the legitimate operator can set the admin email, username, and password, causing permanent initial-instance takeover. This issue has been patched in version 2.3.8."}],"source":{"advisory":"GHSA-h27v-ph7w-m9fp","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-05T14:06:26.362325Z","id":"CVE-2026-42221","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-05-05T14:14:11.906Z"}}]}}