{"id":"CVE-2026-109371","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.","aliases":["GHSA-4hgj-wm6c-q7p2"],"modified":"2026-10-13T02:45:56.610111635Z","published":"2026-10-12T16:05:44.304Z","database_specific":{"cna_assigner":"VulnCheck","cwe_ids":["CWE-306"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109371.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109371.json"},{"type":"ADVISORY","url":"https://github.com/zitadel/zitadel/security/advisories/GHSA-4hgj-wm6c-q7p2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-109371"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/zitadel-3.0.0-before-4.18.0-unauthenticated-username-change-via-login-v1"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/zitadel/zitadel","events":[{"introduced":"573c96d6af6aa8778efd9bff59f9bc0dab94c495"},{"fixed":"6d7878a2e4128517684f43ba7774dd4a9f64ba36"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"3.0.0"},{"fixed":"4.18.0"}]}}],"versions":["v4.12.3","v4.17.3","v4.17.2","v4.17.1","v4.17.0","v4.16.3","v4.16.2","v4.16.1","v4.16.0","v4.15.3","v4.15.2","v4.15.1","v4.15.0","v4.14.0","v4.13.1","v4.13.0","v4.12.2","v4.12.1","v4.12.0","v4.11.1","v4.11.0","v4.10.1","v4.10.0","v4.9.2","v4.9.1","v4.9.0","v4.8.1","v4.8.0","v4.7.6","v4.7.5","v4.7.4","v4.7.3","v4.7.2","v4.7.1","v4.7.0","v4.6.6","v4.6.5","v4.6.4","v4.6.3","v4.6.2","v4.6.1","v4.6.0","v4.5.0","v4.4.0","v4.3.3","v4.3.2","v4.3.1","v4.3.0","v4.2.2","v4.2.1","v4.2.0","v4.1.4","v4.1.3","v4.1.2","v4.1.1","v4.1.0","v4.0.3","v4.0.2","v4.0.1","v3.3.2","v4.0.0","v3.3.1","v3.3.0","v3.2.3","v3.2.2","v3.2.1","v3.2.0","v3.1.0","v3.0.4","v3.0.3","v3.0.2","v3.0.1","v3.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-109371.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N"}]}