The vulnerable code resides in the iframeBox shortcode of the Modal Window WordPress plugin. Because the plugin fails to properly sanitize or escape user supplied attributes, an authenticated attacker with contributor‑level or higher access can embed arbitrary JavaScript that is persisted in the database. When a journaled user opens a page containing the stored iframeBox shortcode, the injected script is executed in that user’s browser, potentially facilitating session hijacking, data exfiltration, or defacement. This exploitation relies on a Stored Cross‑Site Scripting weakness (CWE‑79).

Any WordPress site running the Modal Window – create popup modal window plugin whose version is 6.1.5 or earlier is affected. The plugin is distributed through the WordPress repository and potentially other packaging sites. No additional product or platform variants are listed, so the vulnerability applies to all standard WordPress installations using this plugin.

The CVSS score of 6.4 indicates a medium impact with remote code execution potential limited to script injection. The EPSS score of less than 1% suggests that real‑world exploitation is currently unlikely, and the vulnerability is not catalogued in CISA’s KEV list. However, the attack requires only contributor‑level authentication, a role commonly granted to content authors, making the risk tangible for sites with many active contributors. The exploitation path involves a legitimate login followed by inserting malicious shortcode content, which is then rendered to other users with no further privilege checks.