The WPO365 | MICROSOFT 365 GRAPH MAILER plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'Subject (via wpmail/PHPMailer, e.g. CF7 your-subject)' parameter in all versions up to, and including, 6.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The payload is stored without authentication via any mail-sending feature that forwards a submitter-controlled subject (e.g. a Contact Form 7 form) when the Graph Mailer is enabled but OAuth authorization has not been completed, a default state immediately after plugin activation.

The WPO365 | MICROSOFT 365 GRAPH MAILER plugin for WordPress is vulnerable to Open Redirect in all versions up to, and including, 3.2. This is due to insufficient validation on the redirect url supplied via the 'redirectto' parameter. This makes it possible for unauthenticated attackers to redirect users to potentially malicious sites if 1. they can successfully trick them into performing an action and 2. the plugin is activated but not configured.