Warning: Two Unpatched Citrix NetScaler RCE Zero-Days Under Active Exploitation

On 27 September 2026, Citrix published a security bulletin addressing 8 vulnerabilities affecting customer-managed Citrix NetScaler ADC and Citrix NetScaler Gateway, among which 2 critical unauthenticated Remote Code Execution (RCE) vulnerabilities. Citrix has confirmed active exploitation of these 2 critical vulnerabilities in the wild. CERT-EU recommends updating affected software and running a compromise assessment on those exposed on the internet.