Citrix is warning of exploitation of a recently disclosed critical security flaw in NetScaler ADC and Gateway appliances that could result in exposure of sensitive information.
Tracked as CVE-2023-4966 (CVSS score: 9.4), the vulnerability impacts the following supported versions –

NetScaler ADC and NetScaler Gateway 14.1 before 14.1-8.50
NetScaler ADC and NetScaler Gateway 13.1 before