Stored Cross‑Site Scripting is present in all versions of the WordPress Taxonomy Chain Menu plugin up to and including 1.0.8. The vulnerability arises from the pn_chain_menu shortcode, which fails to sanitize and escape user-supplied attributes. As a result, an authenticated user with contributor privilege or higher can inject malicious JavaScript into a page that will execute for any visitor who views that content. This can lead to theft of session cookies, defacement of the site, or execution of additional attacks against site visitors.

The product affected is the Taxonomy Chain Menu plugin developed by realmag777. All released versions up through 1.0.8 are vulnerable; later releases such as 1.0.9 contain a fix. The plugin is deployed on WordPress sites that have enabled the pn_chain_menu shortcode.

The CVSS score of 6.4 indicates a medium severity attack. The EPSS score of less than 1% suggests the probability of exploitation is low, and the vulnerability is not listed in CISA’s KEV catalog. Because the flaw requires only a contributor‑level account, which is common on many sites, the attack vector is authenticated with moderate privilege. An attacker would need to create or modify content via the shortcode; once injected, the script runs in the browser context of any user that visits the affected page.