This indicates an attack attempt to exploit an SQL Injection Vulnerability in Moodle.
The vulnerabilities is due to insufficient input validation. A remote, authenticated attacker can exploit this vulnerability by sending a crafted request to the target system. Successful exploitation can result in remote code execution under the security context of the database service.
Moodle versions 3.11 to 3.11.4
System Compromise: Remote attackers can add, view, delete or modify data in the database of the affected application
Apply the most recent upgrade or patch from the vendor.