Buffer overflow in the snmpget function in the snmp extension in PHP 5.2.3 and earlier, including PHP 4.4.6 and probably other PHP 4 versions, allows context-dependent attackers to execute arbitrary code via a long value in the third argument (object id).
https://www.exploit-db.com/exploits/4204
https://www.exploit-db.com/exploits/3439
https://exchange.xforce.ibmcloud.com/vulnerabilities/35517
http://secunia.com/advisories/24440
http://retrogod.altervista.org/php_446_snmpget_local_bof.html