Google Analytics by Yoast Plugin for WordPress contains a flaw that allows a stored cross-site scripting (XSS) attack. This flaw exists because the admin/class-admin.php script does not validate input to the manual_ua_code_field field before returning it to users. This may allow an authenticated remote attacker to create a specially crafted request that would execute arbitrary script code in a user’s browser session within the trust relationship between their browser and the server.