Stefan2904

**Name of the Vulnerable Software and Affected Versions** CTFd versions 2.0.0 through 2.2.2 **Description** The issue arises from incorrect username validation in the registration process, allowing an attacker to take over an arbitrary account if the username is known and emails are enabled. To exploit this, an attacker registers with a username identical to the victim's but with added white space, causing a username collision. This results in the victim's account password being reset when a password reset is initiated for the new account. **Recommendations** For CTFd versions 2.0.0 through 2.2.2, as a temporary workaround, consider disabling email functionality on the CTFd instance to prevent password reset exploitation. Restrict access to the registration process to minimize the risk of arbitrary account takeover. Avoid using whitespace in usernames to prevent collisions. At the moment, there is no information about a newer version that contains a fix for this vulnerability.