The string_insert_href function in MantisBT 1.2.0a1 through 1.2.x before 1.2.18 does not properly validate the URL protocol, which allows remote attackers to conduct cross-site scripting (XSS) attacks via the javascript:// protocol.
https://www.mantisbt.org/bugs/view.php?id=17297
https://github.com/mantisbt/mantisbt/commit/05378e00
http://www.debian.org/security/2015/dsa-3120
http://secunia.com/advisories/62101