Ghost is a Node.js content management system. From 6.54.1 until 6.65.0, a validation issue allowed some functionality, such as Webmentions, to be abused by an unauthenticated user to make limited HTTP requests to hosts in the Ghost servers internal network. A successful attack would not result in any response data being returned. This issue is fixed in version 6.65.0.
Weakness
The product checks the state of a resource before using that resource, but the resource’s state can change between the check and the use in a way that invalidates the results of the check.