This vulnerability affects PHPGurukul Online Course Registration 3.1, specifically in the /check_availability.php script. An attacker can manipulate the 'cid' argument to inject SQL commands, potentially compromising the backend database. The vulnerability is remotely exploitable without any privileges or user interaction. The CVSS 4.0 base score is 6.9, indicating medium severity. No official patch or vendor advisory has been published, and the product is not a cloud service, so remediation depends on vendor or user action.

Successful exploitation of this SQL injection vulnerability could allow an attacker to execute arbitrary SQL queries on the database. This may lead to unauthorized data access, modification, or deletion depending on the database permissions. Since the vulnerability is remotely exploitable without authentication, it poses a significant risk to affected installations. However, the CVSS vector indicates low to limited impact on confidentiality, integrity, and availability.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should consider implementing input validation or parameterized queries to mitigate SQL injection risks in the affected script. Monitoring for unusual database activity and restricting database user privileges may also reduce potential impact.