---
id: CVE-2026-105207
title: >-
  ZITADEL 3.0.0 through 3.4.15 and 4.0.0 before 4.17.3 creates links between
  user accounts and external identity providers without verifying a primary
  factor or the caller's permission, including on identify-only Login V2
  sessions and via …
summary: >-
  ZITADEL 3.0.0 through 3.4.15 and 4.0.0 before 4.17.3 creates links between
  user accounts and external identity providers without verifying a primary
  factor or the caller's permission, including on identify-only Login V2
  sessions and via …
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-306
vendor: zitadel
product: zitadel
affected:
  - zitadel < 4.17.3
  - zitadel <= 4.19.4
published: '2026-10-04'
updated: '2026-10-04'
sourceUpdated: '2026-10-04T15:16:31.793'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-105207'
references:
  - url: 'https://github.com/zitadel/zitadel/security/advisories/GHSA-g8gj-gq47-xgf4'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/zitadel-before-4.17.3-account-takeover-via-external-idp-linking
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-04T15:00:34.387Z'
---

## Overview

ZITADEL 3.0.0 through 3.4.15 and 4.0.0 before 4.17.3 creates links between user accounts and external identity providers without verifying a primary factor or the caller's permission, including on identify-only Login V2 sessions and via the User Service V2 AddIDPLink endpoint. An unauthenticated attacker knowing a victim's login name can bind their own external IdP identity to the victim's account and then sign in as the victim.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.