The Visualizer WordPress plugin before 4.0.6 does not restrict a user-supplied URL to safe address ranges before fetching it server-side, allowing users with Contributor-level access and above to perform Server-Side Request Forgery against link-local instance-metadata endpoints. As the fetched response is returned in the reply, the attack is non-blind, enabling retrieval of cloud instance metadata (including IAM credentials) on cloud-hosted sites.
Weakness
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.