Zitadel User Registration Bypass Vulnerability

The open-source identity infrastructure software Zitadel allows administrators to disable the user self-registration. Due to a missing security check in versions prior to 2.64.0, 2.63.5, 2.62.7, 2.61.4, 2.60.4, 2.59.5, and 2.58.7, disabling the "User Registration allowed" option only hid the registration button on the login page. Users could bypass this restriction by directly accessing the registration URL (/ui/login/loginname) and register a user that way. Versions 2.64.0, 2.63.5, 2.62.7, 2.61.4, 2.60.4, 2.59.5, and 2.58.7 contain a patch. No known workarounds are available.