Kirby is a flat-file CMS. In versions prior to 3.5.8.2, 3.6.6.2, 3.7.5.1, and 3.8.1, Kirby is subject to user enumeration due to Improper Restriction of Excessive Authentication Attempts. This vulnerability affects you only if you are using the code or password-reset auth method with the auth.methods option or if you have enabled the debug option in production.

By using two or more IP addresses and multiple login attempts, valid user accounts will lock, but invalid accounts will not, leading to account enumeration. This issue has been patched in versions 3.5.8.2, 3.6.6.2, 3.7.5.1, and 3.8.1. If you cannot update immediately, you can work around the issue by setting the auth.methods option to password, which disables the code-based login and password reset forms.