celestex.pt XSS vulnerability

celestex.pt XSS vulnerability, Open Bug Bounty ID OBB-616672, Custom Code, Coordinated Disclosure based on ISO 29147 guidelines, OWASP XSS Prevention Cheat Sheet, Vulnerable URL: http://www.celestex.pt/produtos.php?id=%22%3E%3C/SCRIPT%3E--!%3E%3CSCRIPT%3Ealert(String.fromCharCode(71,104,48,53,116,80,84))%3C/SCRIPT%3E1〈=1, Vulnerability Reported: 15 May, 2018 11:11 GMT, Vulnerability Verified: 15 May, 2018 11:18 GMT, Website Operator Notified: 15 May, 2018 11:18 GMT, Public Report Published[without any technical details]: 15 May, 2018 11:18 GMT, Public Disclosure: 13 August, 2018 11:11 GMT