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 server's internal network. A successful attack would not result in any response data being returned. This issue is fixed in version 6.65.0.
https://github.com/TryGhost/Ghost/security/advisories/GHSA-322m-ff4g-9vx9
https://github.com/TryGhost/Ghost/releases/tag/v6.65.0
https://github.com/TryGhost/Ghost/pull/30918
https://github.com/TryGhost/Ghost/commit/3f8594eb53de883ac017545c358f59039cb152de