by Kastro
Paper/Archive/CVE-2026-105207

CVE-2026-105207

zitadel zitadel — ZITADEL before 4.17.3 Account Takeover via External IdP Linking

EPSS 0.3%CVSS 9.8
critical.is priorityof 100
34
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 23.9.239 × 204.8No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
zitadel4.0.0 – < 4.17.34.17.3CNA
zitadel3.0.0 – 3.4.15–CNA

Scores by source

VulnCheck (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
VulnCheck (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

advisorygithub.com/zitadel/zitadel/security/advisories/GHSA-g8gj-gq47-xgf4writeupvulncheck.com/advisories/zitadel-before-4.17.3-account-takeover-via-external-idp-linking