Executive Summary

This vulnerability occurs in Zitadel versions starting from 2.53.6, 2.54.3, and 2.55.0, where multi-factor authentication (MFA) was only enforced if the login policy explicitly required it via requireMFA or requireMFAForLocalUsers settings. If a user had set up MFA but the policy did not require it, Zitadel would accept single-factor authenticated sessions as valid, effectively bypassing the second authentication factor. An attacker could exploit this by targeting only the TOTP code (a six-digit code) and bypass password verification entirely, potentially compromising accounts that had 2FA enabled. This flaw weakens the security provided by MFA. The issue was fixed in versions 4.6.0, 3.4.3, and 2.71.18.

Useful 0 Not Useful 0

Impact Analysis

This vulnerability can allow attackers to bypass the second factor of authentication in Zitadel, compromising accounts that have two-factor authentication enabled. By exploiting this flaw, attackers can gain unauthorized access by only using the TOTP code without needing the password, which significantly reduces the security of user accounts and increases the risk of account takeover.

Useful 0 Not Useful 0

Mitigation Strategies

To mitigate this vulnerability, immediately upgrade Zitadel to version 4.6.0, 3.4.3, or 2.71.18 or later, where the issue is fixed. Additionally, review your login policies to ensure that multi-factor authentication is properly required by enabling requireMFA or requireMFAForLocalUsers settings to enforce MFA for all applicable users.

Useful 0 Not Useful 0