This vulnerability in PHPGurukul Online Course Registration 3.1 involves SQL injection via the 'regno' argument processed by /admin/check_availability.php. An attacker can remotely supply crafted input to manipulate SQL queries, potentially impacting data confidentiality, integrity, and availability to a limited extent. The CVSS 4.0 score of 6.9 reflects network attack vector, low complexity, no privileges or user interaction required, but limited impact on confidentiality, integrity, and availability. No official patch or vendor advisory is currently available, and no known exploits in the wild have been reported.

Successful exploitation could allow an attacker to execute unauthorized SQL commands on the backend database, potentially leading to unauthorized data access or modification with limited impact severity. The vulnerability does not require authentication or user interaction, increasing its risk. However, the impact on confidentiality, integrity, and availability is rated as low, indicating partial or limited compromise rather than full system takeover.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, it is recommended to apply input validation and parameterized queries on the 'regno' parameter to prevent SQL injection. Monitoring for unusual database queries and restricting access to the /admin/check_availability.php endpoint may also reduce risk.