source: http://www.securityfocus.com/bid/49235/info

MantisBT is prone to an SQL-injection vulnerability and a cross-site scripting vulnerability.

Exploiting these issues could allow an attacker to steal cookie-based authentication credentials, compromise the application, access or modify data, or exploit latent vulnerabilities in the underlying database.

MantisBT 1.2.6 is vulnerable; other versions may also be affected. 

http://www.example.com/path/search.php?project_id=[XSS]
http://www.example.com/path/core.php?mbadmin=[SQL]