The callme_startcall function in recordings/misc/callme_page.php in FreePBX 2.9, 2.10, and earlier allows remote attackers to execute arbitrary commands via the callmenum parameter in a c action.
https://exchange.xforce.ibmcloud.com/vulnerabilities/74174
http://www.freepbx.org/trac/ticket/5711
http://www.exploit-db.com/exploits/18659
http://secunia.com/advisories/48463
http://seclists.org/fulldisclosure/2012/Mar/234
http://packetstormsecurity.org/files/111028/FreePBX-2.10.0-Remote-Command-Execution-XSS.html