Grav versions before 2.0.16 contain an incomplete default denylist in the Twig sandbox configuration. This flaw allows users who can edit pages to inject Twig code that calls config.get() or config.toArray(), giving them read access to system configuration secrets such as system.cache.redis.password when config_access is enabled. The vulnerability manifests as a confidentiality breach, exposing sensitive data stored in Grav's configuration.

The vulnerability affects all Grav installations using any version prior to 2.0.16. The product is Grav by getgrav, and the issue is tied to the Twig sandbox component within the CMS. No specific patch versions other than 2.0.16+ provide remediation.

The CVSS score of 8.7 indicates high impact, while the EPSS score is not available and the vulnerability is not listed in the CISA KEV catalog. The attack requires the attacker to have page‑edit permissions within a Grav site; from there they can add malicious Twig code to a page. Although the attack vector is likely local or web‑based depending on the site's access controls, the potential for disclosure of configuration secrets places it in a high‑risk category.