Cisco Linksys WRT160N routers contain a flaw that allows a persistent cross-site scripting (XSS) attack. This flaw exists because the application does not validate the 'ddns_enable', 'need_reboot', 'ping_ip', and 'ping_size' parameters upon submission to the /apply.cgi script. This may allow an attacker to create a specially crafted request that would execute arbitrary script code in a user's browser within the trust relationship between their browser and the server.