{"cve":{"cve_id":"CVE-2026-42221","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.00346,"epss_percentile":0.26306,"epss_as_of":"2026-06-23","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_at":"2026-05-04T20:09:37.308000Z","last_modified_at":null,"cvss_v3_score":8.1,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_v3_severity":"HIGH","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":["CWE-306"],"nvd_references":["https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp","https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.8"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-06-28T23:30:18.882139Z"},"effective_severity":"HIGH","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"H","value_label":"High"},{"metric":"PR","name":"Privileges Required","value":"N","value_label":"None"},{"metric":"UI","name":"User Interaction","value":"N","value_label":"None"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"H","value_label":"High"},{"metric":"I","name":"Integrity","value":"H","value_label":"High"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"0xjacky","vendor_name":"0xJacky","product_slug":"nginx-ui","product_name":"nginx-ui","version_start":">= 2.0.0, < 2.3.8","version_start_inclusive":true,"version_end":">= 2.0.0, < 2.3.8","version_end_inclusive":true,"cpe23_uri":"cve5:0xjacky:nginx-ui:>= 2.0.0, < 2.3.8:>= 2.0.0, < 2.3.8"}],"exploit_refs":[],"news":[],"references":[{"url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-h27v-ph7w-m9fp","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.8","source_type":"PATCH","tags":["patch"]}],"timeline":[{"type":"published","at":"2026-05-04T20:09:37.308000Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:54:07.258310Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:07.258310Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:07.258310Z","label":"CVSS score revised","source":"cvelistv5"}]}