Blocksy Companion Stored Cross-Site Scripting Vulnerability

A stored cross-site scripting vulnerability has been identified in the Blocksy Companion plugin for WordPress, affecting all versions through 2.1.10. The issue arises from inadequate input sanitization and output escaping on user-supplied attributes within the blocksy_newsletter_subscribe shortcode. This vulnerability allows authenticated attackers with contributor-level access or higher to inject arbitrary web scripts into pages, which are executed when users access the affected pages.

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 blocksy_newsletter_subscribe shortcode to create a newsletter subscription form. By injecting a script into one of the user-supplied attributes, the script will be executed when the page is viewed.

Remediation

Users are advised to update the Blocksy Companion plugin to version 2.1.11 or later.