Citrix NetScaler Zero-Days Confirmed. Two Critical RCE Flaws. No Patch. Attackers Already Inside.
Citrix confirmed two critical zero-day vulnerabilities in NetScaler ADC and Gateway, CVE-2026-88771 and CVE-2026-88772, both rated CVSS 9.5, actively exploited before patches existed. An unauthenticated attacker can execute arbitrary commands on any NetScaler deployment in its default configuration. Organizations were privately advised by IT suppliers to shut down NetScaler devices before Citrix issued any public bulletin.
The most dangerous detail: patching now will not remove an attacker already inside. NetScaler sits at the network edge, terminating VPN sessions and authenticating users before they reach internal systems. When the front door falls, the attacker is already through. If your organization runs NetScaler, your incident response clock started this weekend.
Read Full Report →The Breach Report is published by Dianne Powers, Fractional CISO and founder of First 48 CISO. Every issue is written from 15 years of enterprise cybersecurity experience across financial services, critical infrastructure, and government sectors. The analysis is practitioner-level, not press release summaries.