The "Project Documentation" feature in MantisBT 1.2.19 and earlier, when the threshold to access files ($g_view_proj_doc_threshold) is set to ANYBODY, allows remote authenticated users to download attachments linked to arbitrary private projects via a file id number in the file_id parameter to file_download.php.

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 the MantisBT (2.3.x before 2.3.2) Timeline include page, used in My View (my_view_page.php) and User Information (view_user_page.php) pages, allows remote attackers to inject arbitrary code (if CSP settings permit it) through crafted PATH_INFO in a URL, due to use of unsanitized $_SERVER['PHP_SELF'] to generate URLs.

MantisBT through 2.3.0 allows arbitrary password reset and unauthenticated admin access via an empty confirm_hash value to verify.php.

A cross-site scripting (XSS) vulnerability in the MantisBT Move Attachments page (move_attachments_page.php, part of admin tools) allows remote attackers to inject arbitrary code through a crafted 'type' parameter, if Content Security Protection (CSP) settings allows it. This is fixed in 1.3.9, 2.1.3, and 2.2.3. Note that this vulnerability is not exploitable if the admin tools directory is removed, as recommended in the "Post-installation and upgrade tasks" of the MantisBT Admin Guide. A reminder to do so is also displayed on the login page.

A cross-site scripting (XSS) vulnerability in the MantisBT Configuration Report page (adm_config_report.php) allows remote attackers to inject arbitrary code (if CSP settings permit it) through a crafted 'config_option' parameter. This is fixed in 1.3.9, 2.1.3, and 2.2.3.

A cross-site scripting (XSS) vulnerability in the MantisBT Configuration Report page (adm_config_report.php) allows remote attackers to inject arbitrary code through a crafted 'action' parameter. This is fixed in 1.3.8, 2.1.2, and 2.2.2.

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).

An XSS vulnerability in the MantisBT Source Integration Plugin (before 2.0.2) search result page allows an attacker to inject arbitrary HTML or JavaScript (if MantisBT's CSP settings permit it) by crafting any valid parameter.

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.