title: [20201105] - Core - User Enumeration in backend login
description: An issue was discovered in Joomla! 3.9.0 through 3.9.22. Improper handling of the username leads to a user enumeration attack vector in the backend login page.
problem types: User Enumeration
affected:
{
product: Joomla! CMS
vendor: Joomla! Project
versions:
status: affected, version: 3.9.0-3.9.22
}