By Eduard Kovacs
Publication Date: 2026-10-05 05:14:00
Citrix NetScaler administrators scrambled over the weekend to protect their appliances after exploitation of a new zero-day vulnerability began.
Administrators initially reported reboots of fully patched NetScaler systems on Friday, and Citrix soon confirmed the existence of another zero-day exploited in the wild.
According to Citrix, the new vulnerability, tracked as CVE-2026-88779 and classified as high severity, is a memory overflow issue affecting NetScaler ADC and NetScaler Gateway instances configured as a SAML SP or SAML IdP.
“Citrix has observed targeted attacks on unmitigated NetScaler deployments which can lead to Denial of Service,” Citrix explained in a blog post. “If the condition is triggered repeatedly, the service may remain unavailable. Our analysis indicates that this issue affects service availability, and we have not identified an impact on the integrity of customer data.”
The attacks were spotted just days after NetScaler…