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CVE-2026-109371GHSA-4hgj-wm6c-q7p2

ZITADEL 3.0.0 before 4.18.0 Unauthenticated Username Change via Login V1

zitadel zitadel
Open in ThreatlineRecord JSON
CVSS
8.8High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.36%Chance of exploitation activity in the next 30 days, higher than 28% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in4.18.0Fixed versionCVE List
Published12 Oct 2026Updated 15 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 2

  • zitadelaffected: 3.0.0 before 4.18.0CVE List
  • zitadelunaffected: 4.18.0CVE List

References 2