CVE-2026-107759
Received Received - Intake

Stored XSS in WPO365 Microsoft 365 Graph Mailer Plugin

Publication date: 2026-10-31

Last updated on: 2026-10-31

Assigner: Wordfence

Description
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.

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Meta Information

Published
2026-10-31
Last Modified
2026-10-31
Generated
2026-10-31
AI Q&A
2026-10-31
EPSS Evaluated
N/A
NVD
CVE-2026-107759
EUVD
EUVD-2026-114654

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
wpo365 WPO365 | MICROSOFT 365 GRAPH MAILER 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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Executive Summary

This vulnerability is a Stored Cross-Site Scripting (XSS) flaw in the WPO365 | MICROSOFT 365 GRAPH MAILER WordPress plugin. It allows unauthenticated attackers to inject malicious scripts via the 'Subject' parameter in mail-sending features like Contact Form 7. The scripts execute when users access infected pages. The issue arises due to insufficient input sanitization and output escaping.

Detection Guidance

Check WordPress admin dashboard for the WPO365 plugin version. If version is 6.2 or lower, the site is vulnerable. Inspect web server logs for unusual POST requests to mail-sending endpoints like Contact Form 7. Look for scripts in the 'Subject' field of emails stored in the database.

Impact Analysis

This vulnerability can lead to unauthorized script execution in browsers, potentially stealing user data, session cookies, or performing actions on behalf of users. Attackers could redirect users to malicious sites or deface web pages. Since it requires no authentication, the risk is high for any site using the vulnerable plugin.

Compliance Impact

This vulnerability could violate GDPR by exposing user data through script injection, leading to unauthorized access or data breaches. For HIPAA, it may compromise protected health information if exploited on healthcare-related sites. Non-compliance risks fines and legal penalties under these regulations.

Mitigation Strategies

Update the WPO365 plugin to the latest version immediately. Disable the plugin if an update is unavailable. Ensure OAuth authorization is completed to prevent unauthenticated access. Monitor for suspicious activity in mail logs and database entries.

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