MantisBT is an open source issue tracker. Prior to version 2.26.1, an unauthenticated attacker who knows a users email address and username can hijack the users account by poisoning the link in the password reset notification message. A patch is available in version 2.26.1. As a workaround, define $g_path as appropriate in config_inc.php.
The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.