includes/specials/SpecialChangePassword.php in MediaWiki before 1.19.14, 1.20.x and 1.21.x before 1.21.8, and 1.22.x before 1.22.5 does not properly handle a correctly authenticated but unintended login attempt, which makes it easier for remote authenticated users to obtain sensitive information by arranging for a victim to login to the attacker's account, as demonstrated by tracking the victim's activity, related to a "login CSRF" issue.