nginx-ui: Unauthenticated First-Run Installer Allows Remote Initial Admin Claim_CVE-2026-42221

{
    "lastseen": "",
    "description": "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.",
    "published": "2026-05-04T20:09:37.308Z",
    "modified": "2026-05-04T20:09:37.308Z",
    "type": "cve",
    "title": "nginx-ui: Unauthenticated First-Run Installer Allows Remote Initial Admin Claim",
    "source": "GitHub_M",
    "references": "https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp\nhttps://github.com/0xJacky/nginx-ui/releases/tag/v2.3.8",
    "id": "CVE-2026-42221",
    "bulletinFamily": "",
    "cwe": [
        "CWE-306"
    ],
    "cvelist": null,
    "sourceData": "0xJacky nginx-ui >= 2.0.0, < 2.3.8",
    "sourceHref": "",
    "cvss": {
        "score": 8.1,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "nginx-ui",
    "version": ">= 2.0.0, < 2.3.8",
    "vendor": "0xJacky",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}