Ninja Forms Stored Cross-Site Scripting Vulnerability

A stored cross-site scripting vulnerability has been identified in the Ninja Forms WordPress plugin, specifically in versions through 3.8.24. This issue arises from inadequate input sanitization and output escaping on user-supplied attributes within the plugin's shortcode. As a result, authenticated attackers with contributor-level access or higher can inject arbitrary web scripts into pages, which will be executed when a user accesses 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 Ninja Forms shortcode to inject scripts. The absence of proper sanitization and escaping on the 'id' attribute of the shortcode in versions through 3.8.24 allows for the execution of injected scripts when the page is viewed.

Remediation

Users are advised to update the Ninja Forms plugin to version 3.8.25 or later.