# CVE-2026-107759: WPO365 MICROSOFT 365 GRAPH MAILER stored cross-site scripting

Source: https://junglewise.ai/threats/cve-2026-107759-the-wpo365-microsoft-365-graph-mailer-plugin-for-wordpress-is  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-31. Updated: 2026-10-31  
License: CC BY 4.0 with a link back

CVE-2026-107759 · Severity: high · CVSS 7.2 · Published 2026-10-31

The WPO365 MICROSOFT 365 GRAPH MAILER plugin for WordPress is used to send emails through Microsoft 365. An unauthenticated attacker can inject malicious scripts through the email subject line when a contact form (like Contact Form 7) submits to the plugin, and these scripts execute in the browsers of anyone who views the affected page. This allows attackers to steal credentials, perform actions on behalf of users, or spread malware without requiring any authentication or plugin configuration.

Vendors: [WPO365](https://junglewise.ai/threats/vendors/wpo365).

## Quick answers

**Is CVE-2026-107759 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-107759 being exploited in the wild.

**How severe is CVE-2026-107759?** High severity, with a CVSS score of 7.2, published 31 October 2026.

**Which products and versions are affected?** WPO365 MICROSOFT 365 GRAPH MAILER up to and including 6.2.

**Is there a fix for CVE-2026-107759?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-107759 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-107759?** Check whether you run WPO365 MICROSOFT 365 GRAPH MAILER at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

This is a stored cross-site scripting (XSS) vulnerability caused by insufficient input sanitization and output escaping of the Subject parameter used in mail-sending functions (wp_mail/PHPMailer). Unauthenticated attackers can exploit this by submitting a contact form with a malicious payload in the subject field when the Graph Mailer is enabled but OAuth authorization has not been completed—a default state immediately after plugin activation. The payload persists in the application and executes whenever users access the injected page.

## Affected products

- WPO365 MICROSOFT 365 GRAPH MAILER up to and including 6.2

## Timeline

- 2026-10-31: disclosed

## References

- [https://plugins.trac.wordpress.org/browser/wpo365-msgraphmailer/tags/6.1/Core/Script_Helpers.php](https://plugins.trac.wordpress.org/browser/wpo365-msgraphmailer/tags/6.1/Core/Script_Helpers.php)
- [https://plugins.trac.wordpress.org/browser/wpo365-msgraphmailer/tags/6.1/Mail/Mailer.php](https://plugins.trac.wordpress.org/browser/wpo365-msgraphmailer/tags/6.1/Mail/Mailer.php)