Citrix NetScaler Zero-Day (CVE-2026-88779) Actively Exploited for Denial-of-Service

A high-severity memory overflow vulnerability in Citrix NetScaler ADC and Gateway, tracked as CVE-2026-88779, is being actively exploited in targeted attacks, leading to denial-of-service. Citrix has released patches, and the U.S. CISA has added the flaw to its Known Exploited Vulnerabilities catalog, urging federal agencies to address it by October 7, 2026. The vulnerability affects deployments configured as a SAML SP or SAML IdP.