Grav versions 2.0.0 through 2.0.17 fail to apply save-time XSS detection to modular pages, allowing authenticated page editors to store Twig-assembled XSS payloads. Attackers with page-edit rights can create modular pages with malicious Twig code that executes in visitor browsers when the parent page is rendered, including in administrator sessions.

Grav versions 2.0.0 through 2.0.17 fail to apply save-time XSS detection to modular pages, allowing authenticated page editors to store Twig-assembled XSS payloads. Attackers with page-edit rights can create modular pages with malicious Twig code that executes in visitor browsers when the parent page is rendered, including in administrator sessions.