Multiple SQL injection vulnerabilities in Zen Cart 1.3.0.2 and earlier allow remote attackers to execute arbitrary SQL commands via (1) GPC data to the ipn_get_stored_session function in ipn_main_handler.php, which can be leveraged to modify elements of $_SESSION; and allow remote authenticated users to execute arbitrary SQL commands via (2) a session id within a cookie to whos_online_session_recreate, (3) the quantity field to the add_cart function, (4) an id[] parameter when adding an item to a shopping cart, or (5) a redemption code when checking out (dc_redeem_code parameter to includes/modules/order_total/ot_coupon.php).
https://exchange.xforce.ibmcloud.com/vulnerabilities/28393
http://www.zen-cart.com/forum/showthread.php?t=43579
http://www.vupen.com/english/advisories/2006/3283
http://www.securityfocus.com/bid/19542
http://www.gulftech.org/?node=research&article_id=00109-08152006