Server-Side Request Forgery (SSRF) in Craft CMS with Asset Uploads Mutations

Required Permissions

The exploitation requires a few permissions to be enabled in the used GraphQL schema:

• "Edit assets in the volume"
• "Create assets in the volume"

Details

The implementation fails to restrict the URL Scheme. While the application is intended to "upload assets", there is no whitelist forcing http or https. This allows attackers to use the Gopher protocol to wrap raw TCP commands.

Impact: Combined with the DWORD bypass, an attacker can hit internal services without triggering any "127.0.0.1" string-matching filters.

Example Payload: gopher://2130706433:6379/_FLUSHALL (Targets local Redis via DWORD).

Remediation Strategy

To prevent mathematical IP obfuscation, the application must normalize the hostname before validation.