Executive Summary

CVE-2026-39713 is a Broken Access Control vulnerability in the WordPress plugin "Mailercloud – Integrate webforms and synchronize website contacts," affecting versions up to and including 1.0.7.

The vulnerability arises from missing authorization, authentication, or nonce token checks in certain plugin functions, which allows unauthenticated users to perform actions that should be restricted to higher-privileged users.

It is classified under the OWASP Top 10 category A1: Broken Access Control and has a CVSS severity score of 5.3, indicating a low severity impact.

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Impact Analysis

This vulnerability allows unauthenticated users to perform privileged actions within the affected plugin, potentially leading to unauthorized access or manipulation of website contacts synchronized through the plugin.

Although such vulnerabilities can be exploited in mass campaigns targeting many websites, this specific flaw is considered unlikely to be exploited with significant impact.

No official patch is currently available, so immediate mitigation involves updating the plugin or seeking assistance from hosting providers or web developers.

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Mitigation Strategies

Immediate mitigation involves updating the affected Mailercloud plugin to a fixed version.

If updating the plugin is not possible, users are advised to seek assistance from their hosting provider or web developer.

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Compliance Impact

The vulnerability is a Broken Access Control issue that allows unauthenticated users to perform actions reserved for higher-privileged users. Such unauthorized access could potentially lead to unauthorized data exposure or modification.

While the CVE description and resources do not explicitly mention compliance with standards like GDPR or HIPAA, broken access control vulnerabilities generally pose risks to data confidentiality and integrity, which are critical aspects of these regulations.

Therefore, if exploited, this vulnerability could negatively impact compliance with regulations that require strict access controls and protection of personal or sensitive data.

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Detection Guidance

This vulnerability is a Missing Authorization (Broken Access Control) issue in the Mailercloud WordPress plugin, allowing unauthenticated users to perform privileged actions. Detection typically involves checking the plugin version and testing access control enforcement on plugin functions.

To detect if your system is vulnerable, first verify if the Mailercloud plugin version is 1.0.7 or earlier, as these versions are affected.

You can check the plugin version on your WordPress site by running the following command on the server hosting WordPress:

• grep -i 'Version' wp-content/plugins/mailercloud-integrate-webforms-synchronize-contacts/readme.txt

Alternatively, you can check the plugin version via WP-CLI:

• wp plugin list | grep mailercloud

To test for the vulnerability, you can attempt to access or invoke plugin functions that require authorization without being authenticated. This may involve sending crafted HTTP requests to endpoints handled by the plugin and observing if unauthorized actions are permitted.

Since no official patch or detailed exploit commands are provided, manual testing or using security scanners that detect broken access control in WordPress plugins may help identify the issue.

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