reCAPTCHA WordPress Plugin Stored Cross-Site Scripting Vulnerability

A stored cross-site scripting vulnerability has been identified in the reCAPTCHA WordPress plugin, affecting versions through 1.6. The issue arises because the plugin fails to properly sanitize and escape certain settings. This flaw enables high-privilege users, such as administrators, to execute stored XSS attacks, even in environments where the unfiltered_html capability is restricted, such as multisite setups.

Impact

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

Reproduction

To reproduce this vulnerability, navigate to the settings page of the reCAPTCHA WordPress plugin. Enter a payload, such as a string including a quotation mark and an event handler (e.g., 'onmouseenter' with an 'alert' command), into the input boxes. After saving the changes, refresh the page and hover the mouse over the input box to trigger the XSS payload.