The Autoptimize plugin for WordPress is vulnerable to stored cross‑site scripting through the LCP Image preload metabox. The flaw arises from insufficient sanitization and escaping of user‑supplied image attributes in the "create_img_preload_tag" function, allowing an attacker with contributor‑level or higher access to inject arbitrary JavaScript that will execute whenever a user views an affected page.

WordPress sites that use the Autoptimize plugin version 3.1.13 or earlier are impacted. The vulnerability applies to any WordPress installation that has the plugin installed and configured with the LCP Image preload feature enabled.

With a CVSS score of 6.4, this issue is considered medium severity. The EPSS score of less than 1% indicates a very low likelihood of exploitation at this time, and it is not listed in the CISA KEV catalog. The attack requires authentication with at least contributor privileges and depends on the attacker being able to alter the image attributes for the preload metabox; once the script is stored, it will run in the context of any visitor to the injected page, potentially compromising user sessions or data.