Executive Summary

CVE-2026-9278 is a Stored Cross-Site Scripting (XSS) vulnerability in the WordPress plugin Form Builder CP versions before 1.2.47.

The plugin does not properly sanitize a form configuration value before storing it and using it in client-side script execution.

This flaw allows authenticated users with Editor-level access or higher to inject malicious scripts into forms.

These malicious scripts are then executed in the browsers of any visitors who view the affected form, even if the site's `unfiltered_html` capability is disabled.

The attack exploits a JavaScript constructor manipulation technique to bypass security restrictions.

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Impact Analysis

This vulnerability can allow an attacker with Editor-level access to inject malicious JavaScript code into forms on your WordPress site.

Any visitor who views a page containing the affected form may have the malicious script executed in their browser.

Potential impacts include theft of user credentials, session hijacking, defacement, or redirection to malicious sites.

Because the vulnerability bypasses the `unfiltered_html` capability restriction, it can be exploited even in multisite networks with stricter content filtering.

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Detection Guidance

This vulnerability can be detected by checking if your WordPress installation uses the Form Builder CP plugin with a version prior to 1.2.47. Since the issue involves stored Cross-Site Scripting (XSS) via form configuration values, detection involves verifying the plugin version and inspecting forms created by users with Editor-level access or higher for suspicious script payloads.

There are no specific commands provided in the available resources to detect this vulnerability directly on your network or system.

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Mitigation Strategies

The immediate step to mitigate this vulnerability is to update the Form Builder CP WordPress plugin to version 1.2.47 or later, where the vulnerability has been fixed.

Additionally, restrict Editor-level and higher user access to trusted users only, as the vulnerability requires authenticated users with Editor-level access or above to exploit.

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Compliance Impact

The vulnerability CVE-2026-9278 allows authenticated users with Editor-level access or higher to perform Stored Cross-Site Scripting (XSS) attacks against visitors of affected pages. Such XSS vulnerabilities can lead to unauthorized access to user data, session hijacking, or malicious script execution in users' browsers.

While the provided information does not explicitly mention compliance with standards like GDPR or HIPAA, the presence of a Stored XSS vulnerability can potentially impact compliance by exposing personal or sensitive data to unauthorized parties or enabling attacks that compromise data integrity and confidentiality.

Therefore, organizations using the affected plugin versions should consider this vulnerability a risk to data protection and privacy requirements mandated by regulations such as GDPR and HIPAA, and apply the fixed version (1.2.47) to mitigate this risk.

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