Warning: Critical Authentication Bypass in Citrix NetScaler ADC & NetScaler Gateway, Patch Immediately!

**Executive summary:** Citrix NetScaler ADC and NetScaler Gateway are affected by CVE-2026-19490, a remote authentication-bypass vulnerability (CVSS v4.0 Base Score 9.3) that can be exploited without authentication when specific configurations (notably SAML actions and Gateway/AAA vservers) are present; the vendor and CCB advise urgent patching, enhanced monitoring, and reporting, and note no current evidence of active exploitation.