CVE-2026-109371

high

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.

References

https://www.vulncheck.com/advisories/zitadel-3.0.0-before-4.18.0-unauthenticated-username-change-via-login-v1

https://github.com/zitadel/zitadel/security/advisories/GHSA-4hgj-wm6c-q7p2

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-97669

Details

Source: Mitre, NVD

Published: 2026-10-12

Updated: 2026-10-15

Risk Information

CVSS v2

Base Score: 8.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:P

Severity: High

CVSS v3

Base Score: 8.2

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L

Severity: High

CVSS v4

Base 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

Severity: High

EPSS

EPSS: 0.00363