Citrix released fixes for the actively exploited CVE-2019-19781 vulnerability impacting Citrix Application Delivery Controller (ADC), Citrix Gateway, and Citrix SD-WAN WANOP appliances. This allows unauthenticated attackers to perform arbitrary code execution. Citrix advises all customers to apply mitigation measures to ADC versions 12.1, 13, 10.5 and 10.3 appliances until a permanent fix will be available. More than 25,000 vulnerable Citrix endpoints were found by security firm Bad Packets last week.
Source: https://www.bleepingcomputer.com/news/security/citrix-patches-cve-2019-19781-flaw-in-citrix-adc-111-and-120/