{"id":"CVE-2026-109371","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-109371","summary":"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…","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.","published":"2026-10-12T17:17:34.547","modified":"2026-10-12T17:17:34.700","cvss":{"score":8.2,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":null,"references":[{"type":"WEB","url":"https://github.com/zitadel/zitadel/security/advisories/GHSA-4hgj-wm6c-q7p2"},{"type":"WEB","url":"https://www.vulncheck.com/advisories/zitadel-3.0.0-before-4.18.0-unauthenticated-username-change-via-login-v1"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-10-12T17:17:34.700"}}