Grav API Plugin is a RESTful API for Grav CMS that provides full headless access to your site's content. Prior to 1.0.6, the Grav API plugin WebhookController.php accepts webhook URLs after only FILTER_VALIDATE_URL syntax validation, and WebhookDispatcher.php initializes cURL without CURLOPT_PROTOCOLS or CURLOPT_REDIR_PROTOCOLS restrictions. An account with api.webhooks.write can submit file, dict, gopher, private-network, or link-local targets, retrieve local files and delivery response bodies, and pivot requests to internal services or cloud metadata endpoints. This issue is fixed in version 1.0.6.