Grav 2.0.0 before 2.2.2 Information Disclosure via Form config-*@ Directives

Grav from 2.0.0 before 2.2.2 contains an information disclosure vulnerability that allows page editors to read protected configuration by adding config-*@ directives to page frontmatter forms. Attackers with page-edit permission can bypass the Twig sandbox config_denied_paths redaction to expose security.salt, plugin credentials, and Redis passwords to all visitors.