Grav before 2.0.20 Cross-Site Scripting via Assets Sandbox
Grav before 2.0.20 contains a cross-site scripting vulnerability in the Twig sandbox policy that allowlists addJs and addCss methods on Grav\Common\Assets without proper output escaping. Page editors can inject arbitrary script by registering malicious assets or injecting attributes, which are rendered unescaped into document head tags and executed for all visitors including administrators.
Grav before 2.0.16 Information Disclosure via Twig Sandbox
Grav before 2.0.16 contains an incomplete default denylist in the Twig sandbox configuration that fails to block access to system configuration secrets. Attackers with page-edit permission can use config.get() or config.toArray() in Twig templates to retrieve sensitive values like system.cache.redis.password when config_access is enabled.
Grav before 2.0.16 Information Disclosure via offsetGet
Grav before 2.0.16 allows sandboxed Twig templates to access sensitive User fields through allow-listed offsetGet() and offsetexists() methods that lack field filtering. Attackers with page-edit permissions can call offsetGet() on User objects to extract hashed passwords and 2FA secrets, enabling offline password cracking and authentication bypass.
Grav CMS before 2.0.16 Origin Validation Bypass via Referer
Grav CMS before 2.0.16 contains an origin validation bypass in the Uri::referrer() and Pages::referrerRoute() methods, which validate the Referer header using an unanchored string prefix match (str_starts_with($referrer, $base)) with no trailing delimiter. An attacker who controls a domain that begins with the victim site's origin (e.g. https://example.com.attacker.tld) can send a request with such a Referer to be treated as same-origin, bypassing the Referer-based origin check.
Grav CMS before 2.0.16 Timing Attack via verifyNonce
Grav CMS before 2.0.16 contains a timing vulnerability in Utils::verifyNonce() that uses non-constant-time string comparison with the === operator instead of hash_equals() for CSRF nonce validation. Attackers can measure response timing differences to recover valid nonce values byte-by-byte through multiple requests, weakening CSRF protection below its intended security margin.
Grav CMS before 2.0.16 Information Disclosure via Twig Sandbox Bypass
Grav CMS before 2.0.16 fails to filter system, site, and theme configuration arrays in sandboxed Twig renders, allowing content editors to read sensitive configuration values. Attackers with page-content edit access can access raw configuration arrays including secrets like cache credentials by using dot notation in Twig templates, bypassing the config_denied_paths restrictions.
Grav CMS before 2.0.16 Path Traversal via media_directory
Grav CMS before 2.0.16 contains a path traversal vulnerability in the media_directory() Twig function that fails to validate filesystem paths, allowing authenticated users to enumerate and access files outside intended scope. Attackers with page authoring privileges can supply arbitrary filesystem paths to media_directory() and use the allow-listed filepath accessor on Medium objects to read file contents of any file matching configured media extensions that the web server process can access.
Grav before 2.0.16 Path Traversal via MediaUploadTrait deleteFile
Grav before 2.0.16 contains a path traversal vulnerability in MediaUploadTrait::deleteFile() that allows authenticated users with media management permissions to delete arbitrary files by supplying filenames with directory traversal sequences. The method validates only the basename portion of the filename while preserving unvalidated directory paths containing ../ sequences that are passed to unlink(), enabling deletion of files outside the intended media storage directory.
A cross-site scripting (XSS) vulnerability in Grav versions 1.7.44 and before, allows remote authenticated attackers to execute arbitrary web scripts or HTML via the onmouseover attribute of an ISINDEX element.