The Grav form plugin renders taxonomy tag and category values in the admin panel using Twig’s |raw filter, bypassing autoescape protection. This flaw permits an editor‑level user to inject persistent JavaScript that runs whenever an administrator views or edits a page. The injected code is stored and can be reused across sessions, making the attack repeatable in the administrative context.

Grav CMS and its Grav Form Plugin, distributed by getgrav. Versions of the form plugin prior to 9.1.0 are vulnerable. The issue is resolved in release 9.1.0, so any deployment using an earlier plugin version is impacted.

The CVSS score is 5.4, indicating moderate severity. EPSS information is not available and the vulnerability is not listed in CISA’s KEV catalog, suggesting limited known exploitation. Exploitation requires an attacker to have editor privileges in order to add or modify taxonomy field values; the attack then triggers when an administrator opens the affected page for viewing or editing.