The vulnerability allows an attacker who has only page‑write rights to run arbitrary PHP code on the Grav CMS web server. In versions up to 2.0.17, the Twig sort filter’s wrapper ignores sandbox restrictions, permitting the use of plain function names such as spl_autoload. Because spl_autoload triggers a PHP include, an attacker can craft a payload – for example, via form front‑matter rendered by the Email plugin – that causes the filter to execute the supplied function, leading to full remote code execution as the web server user.

The affected product is the Grav CMS. Versions up to and including 2.0.17 are impacted. The product vendor is getgrav, with the main product name Grav. Versions 2.0.18 and 2.0.19 or newer are not affected.

The CVSS score of 8.7 indicates high severity. No EPSS data is available, so the likelihood of exploitation cannot be quantified but the vulnerability requires an authenticated user with page‑write privileges, such as those granted the admin.pages or api.pages.write role. The exploit can be delivered through a crafted payload passed to the sort filter, for example via front‑matter in the Email plugin's form. The vulnerability is not currently listed in CISA's KEV catalog.