Grav is a file-based Web platform. Prior to 2.0.4, Grav allowlists the regex_replace filter and function in system/config/security.yaml, and GravExtension::regexReplace() passes an editor-controlled pattern directly to preg_replace(). When security.twig_content.process_enabled is enabled, an authenticated page editor can publish a catastrophically backtracking pattern that consumes PHP worker CPU and denies service to site visitors. This issue is fixed in version 2.0.4.

Grav Login Plugin adds login, basic ACL, and session wide messages to Grav. Prior to 3.8.11, the Grav Login plugin login.regenerate2FASecret task checks only that the pending-session user exists rather than requiring $user->authorized. After submitting a victim's correct password, an attacker can invoke taskRegenerate2FASecret() during the pending TOTP challenge, overwrite twofa_secret, read the replacement secret from the response, calculate a valid code, and complete authentication without the victim's second factor. This issue is fixed in version 3.8.11.

Grav is a file-based Web platform. Prior to 3.8.5, the Login plugin twofa_cancel task accepts a client-controlled _redirect field without a nonce and allows an unauthenticated request to set an external http, https, or protocol-relative Location target. Controller::execute() applies the field when taskTwofa_cancel() sets no redirect, and Grav::getRedirectResponse() accepts the target through Uri::isExternal(), enabling phishing redirects from a trusted Grav host. This issue is fixed in version 3.8.5.

Grav is a file-based Web platform. Prior to 2.0.4, the Grav .htaccess and webserver-configs/htaccess.txt security rules omit the Apache [NC] flag and therefore compare sensitive directory and file-extension patterns case-sensitively. On a case-insensitive filesystem, an unauthenticated requester can use uppercase directory or extension variants to bypass the rules and retrieve files under user/accounts or user/config, including password hashes and security configuration. This issue is fixed in version 2.0.4.

Grav is a file-based Web platform. Prior to 2.0.7, Grav Blueprint::dynamicData() in system/src/Grav/Common/Data/Blueprint.php sends an editor-controlled Class::method provider and arguments to call_user_func_array() without rejecting dangerous callback parameters. An account with admin.pages or api.pages.write can use Grav\Common\Utils::arrayFilterRecursive() as a trampoline with system as the callback, place a command in page frontmatter, and execute that command as the web server user when the page is viewed. This issue is fixed in version 2.0.7.

Grav API plugin (getgrav/grav-plugin-api) before 1.0.14 contains a missing authorization vulnerability in userPassesAuthorize() (AbstractApiController.php). The function fails to consult the calling request's API key scopes, relying instead on the account's raw super-admin flag and ACL grants. As a result, an authenticated attacker holding a scoped API key minted on a privileged account can bypass their declared scope restrictions to access authorize-gated UI metadata and item definitions (sidebar/menubar/widget items and users-list columns/row-actions/filter-tabs) that their key scope should deny, resulting in information disclosure.

Grav Form Plugin before 9.1.19 fails to escape field-definition properties including prepend, append, spacer text, section text, and select option labels in form templates. Attackers with form authoring privileges can inject arbitrary HTML and JavaScript that executes for all form visitors through unescaped |raw filters and unquoted attributes.

Grav before 2.0.15 contains a stored cross-site scripting vulnerability in the audio and video media rendering through the sourceParsedownElement method. The media URL fragment is concatenated unescaped into rawHtml source elements, allowing attackers to inject arbitrary HTML and JavaScript that executes in viewers' sessions.

Grav before 2.0.14 contains a stored cross-site scripting vulnerability in the Security::detectXss() function (system/src/Grav/Common/Security.php). All XSS detection patterns use the PCRE /u (UTF-8) modifier, so a single invalid UTF-8 byte anywhere in page content causes preg_match() to return false for every pattern, silently bypassing the save-time XSS safety gate (Validation::checkSafety()). An authenticated attacker with page-edit permissions (without the security.xss_whitelist privilege) can store malicious JavaScript that executes in the browser of a visitor who views the affected page.

Grav before 2.0.15 contains a stored cross-site scripting vulnerability in the detectXss() function where unpaired quotes in unquoted attribute values bypass event-handler detection. Authenticated editors can inject event handlers like onerror= that pass validation and execute in visitor browsers when page content is rendered.