Grav before 2.0.25 Sandbox Escape via array Filter

Grav 2.0.0 through 2.0.24 contain a Twig content sandbox escape. The array filter (and its identical function form) is on the sandbox allowlist but is registered without the needs_is_sandboxed guard that print_r, vardump, json_encode, yaml_encode and string carry, and its implementation calls toArray() — or falls back to an (array) cast — without consulting the sandbox method allowlist. Because the grav Twig global is the raw Pimple-based dependency injection container, a user who can author Twig in page content can evaluate grav|array to read the container's private $values array, including the un-redacted Config service; a second array cast returns the entire configuration tree, disclosing plugin credentials, SMTP and OAuth secrets, Redis passwords, proxy URLs and the security.* subtree that the sandbox's redaction is meant to hide. Because the payload is stored in page content, the disclosed configuration is rendered to anonymous visitors. Grav 1.7 is not affected as it has no Twig content sandbox. Fixed in Grav 2.0.25.