Mantis Bug Tracker (MantisBT) is an open source issue tracker. In versions 2.28.1 and below, improper escaping of the redirection page (retrieved from the request's Referer header) allows an attacker to inject HTML. While this is generally not directly actionable as modern browsers will URL-encode special characters, on some specific server configurations this could poison the cache, leading to cross-site scripting. This issue has been fixed in version 2.28.2.