Vulnerability · Published Oct 4, 2026 · Assigned by VulnCheck

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

Critical 9.8

In plain English

A critical-severity missing authentication in zitadel from zitadel. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities).

Severity (CVSS 3.1)9.8Critical

Exploit odds (30 days)0.3%top 76.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
zitadel	zitadel	4.0.0 – before 4.17.3
zitadel	zitadel	3.0.0 – through 3.4.15

Weakness: CWE-306 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

GitHub Security Advisory (GHSA-g8gj-gq47-xgf4) vendor-advisory
VulnCheck Advisory: ZITADEL before 4.17.3 Account Takeover via External IdP Linking third-party-advisory