ZITADEL is an open source identity management platform. Versions prior to 3.4.9 and 4.0.0 through 4.12.2 allowed users to bypass organization enforcement during authentication. Zitadel allows applications to enforce an organzation context during authentication using scopes (urn:zitadel:iam:org:id:{id} and urn:zitadel:iam:org:domain:primary:{domainname}). If enforced, a user needs to be part of the required organization to sign in. While this was properly enforced for OAuth2/OIDC authorization requests in login V1, corresponding controls were missing for device authorization requests and all login V2 and OIDC API V2 endpoints.
This allowed users to bypass the restriction and sign in with users from other organizations. Note that this enforcement allows for an additional check during authentication and applications relying on authorizations / roles assignments are not affected by this bypass. This issue has been patched in versions 3.4.9 and 4.12.3.