Direct static code injection vulnerability in admin/save_opt.php in SoftBB 0.1, and possibly earlier, allows remote authenticated users to upload and execute arbitrary PHP code via the cache_forum parameter, which saves the code to info_options.php, which is accessible via a direct request.
https://www.exploit-db.com/exploits/2300
https://exchange.xforce.ibmcloud.com/vulnerabilities/28749
http://www.vupen.com/english/advisories/2006/3478
http://www.securityfocus.com/archive/1/445087/100/0/threaded