Vulnerability in WPO365 | MICROSOFT 365 GRAPH MAILER — CVE-2026-107759
What to do now
Update WPO365 | MICROSOFT 365 GRAPH MAILER to 6.3 or later.
Affected versions
- Everything up to and including 6.2
Affected: WPO365 | MICROSOFT 365 GRAPH MAILER (plugin, wpo365-msgraphmailer)
What the vulnerability is
The WPO365 | MICROSOFT 365 GRAPH MAILER plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'Subject (via wp_mail/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.
Sources
- https://plugins.trac.wordpress.org/browser/wpo365-msgraphmailer/tags/6.1/Core/Script_Helpers.php#L142
- https://plugins.trac.wordpress.org/browser/wpo365-msgraphmailer/tags/6.1/Mail/Mailer.php#L71
- https://plugins.trac.wordpress.org/browser/wpo365-msgraphmailer/tags/6.1/Services/Ajax_Service.php#L284
- https://plugins.trac.wordpress.org/browser/wpo365-msgraphmailer/tags/6.1/Services/Log_Service.php#L80
- https://plugins.trac.wordpress.org/browser/wpo365-msgraphmailer/tags/6.1/apps/dist/wizard-chunk-G9IB6WhS.js#L154
- https://plugins.trac.wordpress.org/changeset?reponame=&old=3752919%40wpo365-msgraphmailer&new=3752919%40wpo365-msgraphmailer