An XSS issue was discovered in admin/install.php in MantisBT before 1.3.12 and 2.x before 2.5.2. Some variables under user control in the MantisBT installation script are not properly sanitized before being output, allowing remote attackers to inject arbitrary JavaScript code, as demonstrated by the $f_database, $f_db_username, and $f_admin_username variables. This is mitigated by the fact that the admin/ folder should be deleted after installation, and also prevented by CSP.
MantisBT before 1.3.11, 2.x before 2.3.3, and 2.4.x before 2.4.1 omits a backslash check in string_api.php and consequently has conflicting interpretations of an initial \/ substring as introducing either a local pathname or a remote hostname, which leads to (1) arbitrary Permalink Injection via CSRF attacks on a permalink_page.php?url= URI and (2) an open redirect via a login_page.php?return= URI.
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).
A cross-site scripting (XSS) vulnerability in view_filters_page.php in MantisBT before 2.2.1 allows remote attackers to inject arbitrary JavaScript via the 'view_type' parameter.