Argument injection vulnerability in certain PHP 4.x and 5.x applications, when used with sendmail and when accepting remote input for the additional_parameters argument to the mb_send_mail function, allows context-dependent attackers to read and create arbitrary files by providing extra -C and -X arguments to sendmail. NOTE: it could be argued that this is a class of technology-specific vulnerability, instead of a particular instance; if so, then this should not be included in CVE.
http://www.vupen.com/english/advisories/2006/0772
http://www.securityfocus.com/bid/16878
http://www.securityfocus.com/archive/1/426342/100/0/threaded
http://www.novell.com/linux/security/advisories/05-05-2006.html