What’s Vulnerable › Vulnerabilities

CVE-2026-105207: ZITADEL before 4.17.3 Account Takeover via External IdP Linking

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-04 · updated 2026-10-29
• Weakness: CWE-306

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.

Affected products

• zitadel: from 4.0.0 before 4.17.3 — fixed in 4.17.3

How to fix

Upgrade to a fixed version: zitadel 4.17.3. Check the vendor advisory for mitigations.

References

• https://github.com/zitadel/zitadel/security/advisories/GHSA-g8gj-gq47-xgf4
• https://www.vulncheck.com/advisories/zitadel-before-4.17.3-account-takeover-via-external-idp-linking

Get alerted when CVE-2026-105207 or the next vulnerability affects your stack