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.
packetstormsecurity.org/files/111028/FreePBX-2.10.0-Remote-Command-Execution-XSS.html
seclists.org/fulldisclosure/2012/Mar/234
secunia.com/advisories/48463
www.exploit-db.com/exploits/18649
www.exploit-db.com/exploits/18659
www.freepbx.org/trac/ticket/5711
www.securityfocus.com/bid/52630
exchange.xforce.ibmcloud.com/vulnerabilities/74174