Zitadel is an open source identity management system. ZITADEL uses HTML for emails and renders certain information such as usernames dynamically. That information can be entered by users or administrators. Due to a missing output sanitization, these emails could include malicious code. This may potentially lead to a threat where an attacker, without privileges, could send out altered notifications that are part of the registration processes. An attacker could create a malicious link, where the injected code would be rendered as part of the email. On the user's detail page, the username was also not sanitized and would also render HTML, giving an attacker the same vulnerability. While it was possible to inject HTML including javascript, the execution of such scripts would be prevented by most email clients and the Content Security Policy in Console UI. This vulnerability is fixed in 2.58.1, 2.57.1, 2.56.2, 2.55.5, 2.54.8 2.53.9, and 2.52.3.

Zitadel is an open source identity management system. ZITADEL administrators can enable a setting called "Ignoring unknown usernames" which helps mitigate attacks that try to guess/enumerate usernames. If enabled, ZITADEL will show the password prompt even if the user doesn't exist and report "Username or Password invalid". Due to a implementation change to prevent deadlocks calling the database, the flag would not be correctly respected in all cases and an attacker would gain information if an account exist within ZITADEL, since the error message shows "object not found" instead of the generic error message. This vulnerability is fixed in 2.58.1, 2.57.1, 2.56.2, 2.55.5, 2.54.8, and 2.53.9.