A problematic issue exists in FastAdmin related to improper path restriction within the `/index/ajax/lang` component. This allows for path traversal, potentially enabling remote attackers to access sensitive information. The issue affects an unknown functionality within the `/index/ajax/lang` file, where manipulation of the `lang` parameter can lead to unauthorized data access. Reports indicate that approximately 14,000 instances may be affected yearly. Exploitation of this issue has been publicly disclosed and is being actively used to retrieve database details. The **API endpoint** `/index/ajax/lang` is involved, and the `lang` parameter is a **vulnerable parameter**.