LinkAce is a self-hosted archive to collect website links. Versions prior to 2.5.3 block direct requests to private IP literals, but still performs server-side requests to internal-only resources when those resources are referenced through an internal hostname. This allows an authenticated user to trigger server-side requests to internal services reachable by the LinkAce server but not directly reachable by an external user. Version 2.5.3 patches the issue.
CWE-918