Hello Khant, thanks for your question. We have got a procedure for reporting potential security issue: https://docs.moodle.org/dev/Moodle_security_procedures#How_can_I_report_a_security_issue.3F Can you please submit a ticket and provide more details on Moodle version you are using.
Security and privacy
How to prevent script tag in search URL
Re: How to prevent script tag in search URL