Citrix has disclosed that vulnerable NetScaler Application Delivery Controller and Gateway instances have been targeted in ongoing attacks leveraging the critical remote code execution flaw, tracked as CVE-2023-3519, The Hacker News reports. Threat actors could successfully exploit the vulnerability, which impacts various NetScaler ADC and NetScaler Gateway appliances, provided that the targeted devices are configured to either be a Gateway or authorization and accounting virtual server, according to Citrix, which has already released updates to address the vulnerability along with an improper input validation bug, tracked as CVE-2023-3466, and the improper privilege management flaw, tracked as CVE-2023-3467. However, organizations leveraging NetScaler ADC and NetScaler Gateway version 12.1, which have reached end-of-life, were urged to upgrade to newer versions of the appliance software. Such attacks have prompted the inclusion of CVE-2023-3519 in the Cybersecurity and Infrastructure Security Agency's Known Exploited Vulnerabilities catalog, with federal agencies ordered to remediate the flaw by Aug. 9.