🛡️ **BREAKING: Citrix NetScaler Zero-Day RCE Under Active Exploitation—Web Shells Deployed Globally**
Published Tuesday, September 29, 2026 at 05:39 PM PT BLUF Attackers are exploiting unpatched remote code execution (RCE) vulnerabilities in Citrix NetScaler (CVE-2026-88771, CVE-2026-88772) to deploy web shells across the internet. Attacks have been active for at least three weeks. Organizations using NetScaler should assume compromise if unpatched and immediately engage incident response. DETAILS Citrix confirmed two high-severity NetScaler RCE zero-days are being exploited in active attacks globally Malicious actors deploy web shells post-exploitation, enabling persistent backdoor access and lateral movement Exploitation has occurred undetected for at least three weeks, suggesting widespread compromise before public disclosure GreyNoise telemetry confirms mass/swarming attack activity (149+ probe attempts from single IP: 149.104.78.141 on 24 September 2026) Vulnerabilities remain unpatched as of this alert date; no vendor patch timeline confirmed in provided material IMPACT Any organization running unpatched Citrix NetScaler appliances (commonly used as gateway/VPN endpoints) is likely compromised. Affected systems provide attackers direct access to internal networks, credential theft opportunities, and lateral movement vectors. Defense contractors have been targeted; global scope confirmed. ...