Details ================ Software: MailChimp for WordPress Version: 3.1.5,4.0.10 Homepage: http://wordpress.org/plugins/mailchimp-for-wp/ Advisory report: https://security.dxw.com/advisories/reflected-xss-in-mailchimp-for-wordpress-could-allow-an-attacker-to-do-almost-anything-an-admin-user-can/ CVE: Awaiting assignment CVSS: 5.8 (Medium; AV:N/AC:M/Au:N/C:P/I:P/A:N) Description ================ Reflected XSS in MailChimp for WordPress could allow an attacker to do almost anything an admin user can Vulnerability ================ If an attacker can trick a logged-in admin user intoA visiting a particular URL, they can execute JavaScript in the useras browser which can perform almost any action that the user can. Proof of concept ================ Assuming you have the site running on http://localhost/ with the plugin activated, visit this URL in a browser without reflected XSS mitigation measures (i.e. Firefox): http://localhost/wp-admin/admin.php?page=mailchimp-for-wp-integrations&integration=%3Cscript%3Ealert%281%29%3C%2Fscript%3E Mitigations ================ Update to versionA 4.0.11 or later. Disclosure policy ================ dxw believes in responsible disclosure. Your attention is drawn to our disclosure policy: https://security.dxw.com/disclosure/ Please contact us on security@dxw.com to acknowledge this report if you received it via a third party (for example, plugins@wordpress.org) as they generally cannot communicate with us on your behalf. This vulnerability will be published if we do not receive a response to this report with 14 days. Timeline ================ 2016-03-23: Discovered 2016-12-07: Reported toA support@ibericode.com 2016-12-07: Requested CVE 2016-12-07: Vendor first replied 2016-12-09: Vendor reported fixed inA 4.0.11 2016-12-13: Advisory published Discovered by dxw: ================ Tom Adams Please visit security.dxw.com for more information.