If anyone is looking for a way to scan their networks to find Citrix/Netscaler ADC/Gateway appliances vulnerable to CVE-2019-19781....Open Web Application Security Project (OWASP) has a free and open-source tool called OWASP Nettacker which can scan the IP ranges and report vulnerable devices. Also useful to check/verify if the mitigation steps have been applied: https://medium.com/@securestep9/detecting-citrix-cve-2019-19781-with-owasp-nettacker-c460c5912c77