GMS-2022-5560: Kirby CMS vulnerable to user enumeration in the code-based login and password reset forms

Under normal circumstances, entering an invalid email address results in a “fake” login code form that looks exactly like the one of an existing user (unless debugging is enabled). However, the code that handles the creation of a code challenge (for code-based login or password reset) didn’t catch errors that occurred while the challenge request was processed. If the challenge itself runs into an error (e.g. if the email could not be sent), attackers could tell existing users (where the challenge code is called) from non-existing users (where the challenge code is not called and therefore does not output an error). If you are using the user.login:failed hook and any exception is thrown within the hook, attackers could see that the user does not exist. As long as no error occurs during challenge creation and during the processing of the user.login:failed hook, your Kirby sites are not affected by this vulnerability.