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.

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Mon, 12 Oct 2026 16:30:00 +0000

Type Values Removed Values Added
Description 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.
Title ZITADEL 3.0.0 before 4.18.0 Unauthenticated Username Change via Login V1
First Time appeared Zitadel
Zitadel zitadel
Weaknesses CWE-306
CPEs cpe:2.3:a:zitadel:zitadel:*:*:*:*:*:*:*:*
Vendors & Products Zitadel
Zitadel zitadel
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L'}

cvssV4_0

{'score': 8.8, 'vector': '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'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-12T16:05:44.304Z

Reserved: 2026-10-12T14:23:25.691Z

Link: CVE-2026-109371

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-12T17:17:34.547

Modified: 2026-10-12T17:17:34.700

Link: CVE-2026-109371

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses