Yes, a backend API server is vulnerable to CSRF. In fact, any web application that accepts requests from unauthenticated users is vulnerable to CSRF attacks. This includes both the front-end and backend portions of an application. An attacker can exploit a CSRF vulnerability by convincing a user to click on a malicious link or by submitting a malicious form. The attack will typically execute without the user's knowledge or consent, and it can be used to perform any action that the target user is authorized to do on the target website. CSRF...