CVE-2026-105215

Critical

Description

ZITADEL before 3.4.14 and 4.x before 4.16.2 contains an authentication bypass in the hosted Login V1 UI because the 'external account not found' registration endpoint trusts client-supplied external identity fields without a completed IdP callback. Unauthenticated attackers can submit forged IDPConfigID and ExternalUserID values to pre-create an account bound to a victim's external IdP identity, which the victim's later genuine external login then signs into.

SeverityCritical

CVSS9.1

Exploit probability—

ProductZitadel

PublishedOct 4, 2026

First seenOct 4, 2026

Weakness typeCWE-290CWE-290

How to fix

Update

zitadel zitadel4.16.2, 3.4.14 or later

Vendor advisories

github.com/zitadel/zitadel/security/advisories/GHSA-738m-7888-jfv8

Affected products

Product	Affected versions	Fixed in
zitadel zitadel	4.0.0 ≤ v < 4.16.2, v < 3.4.14	4.16.2, 3.4.14

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