New security flaw found in Citrix NetScaler devices despite recent patches

Cybersecurity researchers and federal agencies have identified a new zero-day vulnerability, tracked as CVE-2026-88779, affecting Citrix NetScaler ADC and Gateway appliances. This memory overflow flaw specifically impacts devices configured as a Security Assertion Markup Language (SAML) identity or service provider. Citrix confirmed the issue late Friday following reports of active exploitation, which can result in denial of service attacks. The vendor released security advisories and necessary patches by Saturday night to address the flaw.

This development is particularly critical as it follows the recent patching of two other exploited vulnerabilities in the same product line. Because the bug targets single sign-on authentication processes, it poses a significant risk to organizational stability. Companies using these appliances should immediately verify their configurations, apply the latest updates, and monitor their systems to protect sensitive data and maintain service availability.