Max PeintnerandGitHub
a331e5b7ba
# Which Problems Are Solved A `login_hint` that resolves an organization via domain discovery but matches no existing user is no longer automatically redirected to the organization's external IdP when enumeration protection (`ignoreUnknownUsernames`) is active on the request context. #12369 combined the unknown-user IdP redirect into a single condition, but gated it with `&& !ignoreUnknownUsernames`: ```ts if ((!effectiveLoginSettings?.allowLocalAuthentication || discoveredOrganization) && !ignoreUnknownUsernames) { ``` Since the flag is resolved from the pre-discovery context (the instance default settings — during domain discovery there is no organization context yet), enabling enumeration protection instance-wide disables the redirect even for IdP-only organizations (`allowLocalAuthentication: false`). The flow falls through to `preventUserEnumeration()` and strands the user on a decoy Password screen for an account that does not exist; the Back button re-enters the auto-submit loop and dead-ends identically. This breaks silent-SSO first logins where the external IdP is supposed to create the account on first authentication (Login V2). The guard is also counterproductive on its own terms: existing users of the same org still auto-redirect to the IdP, so the divergent treatment acts as an enumeration oracle — redirect means the user exists, password screen means it doesn't. And it protects nothing in practice, since the IdP remains reachable manually via the account switcher → login-name screen → IdP button. # How the Problems Are Solved Split the condition by what known users of the resolved organization actually experience, so unknown usernames always mimic the known-user flow: ```ts if ( !effectiveLoginSettings?.allowLocalAuthentication || (discoveredOrganization && !ignoreUnknownUsernames) ) { ``` - **Local authentication disabled (IdP-only org):** redirect unknown usernames to the single allowed IdP regardless of `ignoreUnknownUsernames`. Known users are auto-redirected there, so the identical redirect is precisely what keeps unknown usernames indistinguishable — and it restores first-login account creation via the external IdP. - **Local authentication enabled:** known (password) users see the password screen, so the decoy password screen remains the indistinguishable behavior and enumeration protection keeps gating the discovery-based IdP redirect, as introduced by #12369. Adds regression tests for both cases: domain discovery into an IdP-only org with `ignoreUnknownUsernames: true` expects the IdP redirect; discovery into a local-auth org expects the decoy `/password` redirect with no IdP flow started.
The Identity Infrastructure for Developers
ZITADEL is an open-source identity and access management platform built for teams that need more than basic auth. Whether you're securing a SaaS product, building a B2B platform, or self-hosting a production IAM stack — ZITADEL gives you everything out of the box: SSO, MFA, Passkeys, OIDC, SAML, SCIM, and a battle-tested multi-tenancy model.
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| ZITADEL | FusionAuth | Keycloak | Auth0/Okta | |
|---|---|---|---|---|
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"username": "[email protected]",
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"email": { "email": "[email protected]", "sendCode": {} }
}'
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