. Since that date, the official PHP development team has provided no security updates or bug fixes
If an upgrade is not immediately possible, use a Web Application Firewall (WAF) and strictly sanitize all user inputs . php version 5640 vulnerabilities link
https://nvd.nist.gov/vuln/search/results?form_type=Basic&results_type=overview&query=PHP+5.6.40&search_type=all . Since that date