Attackers are probing, exploits already available
https://www.bleepingcomputer.com/news/security/cisa-releases-test-tool-for-citrix-adc-cve-2019-19781-vulnerability/
DHS CISA released a public domain tool designed to help security staff to test if their organizations are vulnerable to ongoing attacks that might target the CVE-2019-19781 security flaw impacting the Citrix Application Delivery Controller (NetScaler ADC) and Citrix Gateway (NetScaler Gateway) products.
"The Cybersecurity and Infrastructure Security Agency (CISA) has released a utility that enables users and administrators to test whether their Citrix Application Delivery Controller (ADC) and Citrix Gateway software is susceptible to the CVE-2019-19781 vulnerability," says the DHS agency.