{"schema":"threatline.record/2","record":{"id":"CVE-2026-109371","aliases":["GHSA-4hgj-wm6c-q7p2"],"summary":"ZITADEL 3.0.0 before 4.18.0 Unauthenticated Username Change via Login V1","details":"ZITADEL 3.0.0 before 4.18.0 contains a missing authentication vulnerability in the hosted Login V1 UI, where the change-username handler acts on the account bound to a login flow before any factor is verified. Unauthenticated attackers can submit a victim's login name and then post a new username to rename any active human user, including administrators, locking them out.","categories":["Unclassified"],"product":"zitadel","vendor":"zitadel","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-109371","source_modified_at":"2026-10-15T02:55:04.399Z","fetched_at":"2026-10-23T18:48:36.087640Z","product":"zitadel","vendor":"zitadel","versions":[{"version":"3.0.0","status":"affected","versionType":"semver","lessThan":"4.18.0"},{"version":"4.18.0","status":"unaffected","versionType":"semver"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-109371","source_modified_at":"2026-10-15T02:55:04.399Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"zitadel","ecosystem":null},"version":"4.18.0","basis":"first unaffected version stated in the CVE record"}],"cvss":8.8,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00363,"percentile":0.28993,"score_date":"2026-10-23"},"published_at":"2026-10-12T16:05:44.304Z","modified_at":"2026-10-15T02:55:04.399Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-109371","fetched_at":"2026-10-23T18:48:36.087640Z","source_modified_at":"2026-10-15T02:55:04.399Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-109371","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/zitadel/zitadel/security/advisories/GHSA-4hgj-wm6c-q7p2","tags":["vendor-advisory"]},{"source":"CVE List","url":"https://www.vulncheck.com/advisories/zitadel-3.0.0-before-4.18.0-unauthenticated-username-change-via-login-v1","tags":["third-party-advisory"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"none","automatable":"yes","technical_impact":"partial","assessed_at":"2026-10-15T02:54:54.525845Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-15T02:55:04.399Z","content_hash":"324dbbcddc78b87cc32d97718384d7ff2661cb21fdad3f79a6e462f188c3e621"}}