CVE-2026-105215

CRITICAL 9.1

ZITADEL before 4.16.2 Account Pre-Hijacking via Forged External IdP Callback

CVSS Score

9.1

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-290
Vendor	zitadel
Product	zitadel
Published	Oct 4, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Affected Versions

zitadel / zitadel

0 < 4.16.2

zitadel / zitadel

0 < 3.4.14

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/zitadel/zitadel/security/advisories/GHSA-738m-7888-jfv8 vulncheck.com: https://www.vulncheck.com/advisories/zitadel-before-4.16.2-account-pre-hijacking-via-forged-external-idp-callback

Credits

🔍 Ibonok livio-a IAM-marco 🔍 AdamKorcz