A cross-site scripting (XSS) vulnerability in MantisBT before 2.1.1 allows remote attackers to inject arbitrary HTML or JavaScript (if MantisBT\'s CSP settings permit it) by modifying \'window_title\' in the application configuration. This requires privileged access to MantisBT configuration management pages (i.e., administrator access rights) or altering the system configuration file (config_inc.php).