CVE-2026-105207

Critical

Description

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.

SeverityCritical

CVSS9.8

Exploit probability—

ProductZitadel

PublishedOct 4, 2026

First seenOct 4, 2026

Weakness typeCWE-306Missing authentication for critical function

How to fix

Update

zitadel zitadel4.17.3 or later

Vendor advisories

github.com/zitadel/zitadel/security/advisories/GHSA-g8gj-gq47-xgf4

Affected products

Product	Affected versions	Fixed in
zitadel zitadel	4.0.0 ≤ v < 4.17.3, 3.0.0 ≤ v ≤ 3.4.15	4.17.3

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