The send_message.php endpoint in SourceCodester Simple Public Chat Room 1.0 is vulnerable to Cross-Site Request Forgery (CSRF). The application does not implement any CSRF-protection mechanisms such as tokens, nonces, or same-site cookie restrictions. An attacker can create a malicious HTML page that, when visited by an authenticated user, will automatically submit a forged POST request to the vulnerable endpoint. This request will be executed with the victim's privileges, allowing the attacker