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High · 8.1 CVE-2026-105211 EUVD-2026-92104GHSA-mq63-7hcv-jfrc

ZITADEL before 4.17.1 Authentication Bypass via Login V2 OTP returnCode

Published Oct 4, 2026 · Updated Oct 5, 2026 · Assigned by VulnCheck

Description

ZITADEL before 4.17.1 contains an authentication bypass vulnerability in Login V2 that allows unauthenticated attackers to take over accounts by obtaining OTP codes via the returnCode delivery type. Attackers knowing a login name of a victim with OTP-Email and OTP-SMS enrolled can read both codes from server-action responses to gain MFA-authenticated sessions, including administrator takeover.

Affected products

VendorProductAffectedFixed
zitadel zitadel < 4.17.1 4.17.1

References