source: http://www.securityfocus.com/bid/11980/info

2fax is prone to a buffer overflow vulnerability. This issue is exposed when the software performs tab expansion operations while converting files. Since files may originate from an external or untrusted source, this issue is considered remote in nature.

Successful exploitation will result in execution of arbitrary code in the context of the user running the application. 

https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/sploits/24984.zip