Ultra Addons for Contact Form 7 Stored Cross-Site Scripting Vulnerability

A stored cross-site scripting vulnerability has been identified in the Ultra Addons for Contact Form 7 WordPress plugin, affecting all versions through 3.5.21. The vulnerability arises from inadequate input sanitization and output escaping of user-supplied attributes in the UACF7_CUSTOM_FIELDS shortcode. This flaw allows authenticated attackers with contributor-level access or higher to inject arbitrary scripts into pages, which are executed when users access the affected page.

Impact

Exploitation of this vulnerability allows for stored cross-site scripting, where injected scripts are executed in the context of the user viewing the page.

Reproduction

To reproduce this vulnerability, an authenticated user with contributor-level access or higher can use the UACF7_CUSTOM_FIELDS shortcode to inject scripts. The lack of proper sanitization and escaping on the attributes of this shortcode in versions through 3.5.21 allows the injection of malicious scripts that will be executed when the page is viewed.

Remediation

Users are advised to update the Ultra Addons for Contact Form 7 plugin to version 3.5.22 or later, where this vulnerability has been patched.