Grav 1.7.50.2 allows admins to enter JavaScript via the Home Page editor. NOTE: the relevance of this for stored XSS is disputed because admins are allowed to modify templates, install plugins, and upload other executable content.

Grav is a flat-file CMS. In versions 2.0.0-rc.1 through 2.0.21, the Twig content sandbox fails to restrict the dump and serialize filters (print_r, vardump, json_encode, yaml_encode, string): GravExtension::assertSandboxDumpSafe() determines sandbox state by calling SandboxExtension::isSandboxed() without a Source argument, which reports only the global sandbox flag that Grav never enables, so the guard added in GHSA-mc5q-6hpj-rp7j never executes. As a result, an authenticated user with page-edit rights can render {{ config|print_r }} in page content with Twig processing enabled and dump Grav's entire merged configuration — print_r reflects the real Config object held in a private property of the SandboxConfig facade, bypassing its path redaction — exposing plugin secrets such as SMTP credentials, API tokens, webhook secrets and cache backend passwords. Grav 1.7 is not affected because it ships no Twig content sandbox. The issue is fixed in 2.0.22, where the affected filters are registered with Twig's needs_is_sandboxed flag.

Grav versions before 1.10.55 contain a path traversal vulnerability in the admin plugin's Save As action that fails to validate the language code parameter. An authenticated admin user with admin.pages.create permission can supply directory traversal sequences in the lang POST field to write arbitrary .md files outside the pages directory with attacker-controlled content.

Grav Shortcode Core before 6.2.5 contains stored cross-site scripting vulnerabilities in the [lorem] tag parameter and [details] summary parameter that are written to rendered pages without escaping. Attackers with page-edit access can inject arbitrary HTML and JavaScript that executes in the browsers of all page visitors, including administrators.

The Grav Form plugin (getgrav/grav-plugin-form) versions 8.0.6 through 9.1.19 select the reCAPTCHA version to validate based solely on which response field key is present in the submitted payload. On a site configured for reCAPTCHA v3, an anonymous attacker can place their v3 token under the v2 field name (g-recaptcha-response instead of token), causing validation to use the v2 branch, which never applies the score threshold or verifies the expected action. This results in a complete bypass of reCAPTCHA v3 bot protection. The issue is fixed in version 9.1.20.

Grav Admin (getgrav/grav-plugin-admin2) versions <= 2.0.19 contain a stored cross-site scripting vulnerability in the tHtml() function (src/lib/stores/i18n.svelte.ts), which substitutes untrusted parameters such as usernames into translation templates before parsing the result as markdown. Grav's server-side username validation (DataUser::isValidUsername) blocks filesystem-dangerous characters but not <, >, ", or ', allowing an attacker to register a username containing an HTML payload. When an administrator views a UI surface that renders the username through tHtml()—such as the two-factor force-disable confirmation prompt or the 'page is locked' editor notice—the payload executes in their authenticated session. Fixed in 2.0.21.

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.

The Grav API plugin (getgrav/grav-plugin-api) before 1.0.18 does not apply the API-key scope cap in the injectSecurityTab() function of BlueprintController when deciding whether a page's security/permissions blueprint section is editable. Because the function performs raw isSuperAdmin()/hasPermission() checks without a request parameter, it cannot enforce scopeAllows(). A caller holding a scoped API key may therefore see (and potentially edit) page permission fields beyond the scope granted to the key. The end-to-end write-time impact was not fully confirmed by the reporter.

The getgrav/grav-plugin-api plugin before 1.0.18 does not enforce API-key scope in the requireNotSuperTarget() function in UsersController.php across seven sensitive user-management endpoints. The check uses isSuperAdmin() on the acting account rather than verifying whether the specific API key carries super authority (via isSuperWithinScope()). As a result, an API key scoped below full super authority but belonging to a super-admin account can act against other super-admin accounts—disabling their 2FA, deleting their avatar, minting new API keys under their identity, or deleting their existing API keys.

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.