SEPPMail's web frontend, user input is not embedded correctly in the web page and therefore leads to cross-site scripting vulnerabilities (XSS).

The SEPPmail solution is vulnerable to a Cross-Site Scripting vulnerability (XSS), because user input is not correctly encoded in HTML attributes when returned by the server.SEPPmail 11.1.10 allows XSS via a recipient address.

WP Mailster 1.6.18.0 allows XSS when a victim opens a mail server's details in the mst_servers page, for a crafted server_host, server_name, or connection_parameter parameter.

PHPMailer 6.4.1 and earlier contain a vulnerability that can result in untrusted code being called (if such code is injected into the host project's scope by other means). If the $patternselect parameter to validateAddress() is set to 'php' (the default, defined by PHPMailer::$validator), and the global namespace contains a function called php, it will be called in preference to the built-in validator of the same name. Mitigated in PHPMailer 6.5.0 by denying the use of simple strings as validator function names.

PHPMailer before 6.5.0 on Windows allows remote code execution if lang_path is untrusted data and has a UNC pathname.

PHPMailer 6.1.8 through 6.4.0 allows object injection through Phar Deserialization via addAttachment with a UNC pathname. NOTE: this is similar to CVE-2018-19296, but arose because 6.1.8 fixed a functionality problem in which UNC pathnames were always considered unreadable by PHPMailer, even in safe contexts. As an unintended side effect, this fix eliminated the code that blocked addAttachment exploitation.

PHPMailer before 6.1.6 contains an output escaping bug when the name of a file attachment contains a double quote character. This can result in the file type being misinterpreted by the receiver or any mail relay processing the message.

PHPMailer before 5.2.27 and 6.x before 6.0.6 is vulnerable to an object injection attack.

The WP Mailster plugin before 1.5.5 for WordPress has XSS in the unsubscribe handler via the mes parameter to view/subscription/unsubscribe2.php.

PHPMailer 5.2.23 has XSS in the "From Email Address" and "To Email Address" fields of code_generator.php.