Citrix Releases Emergency NetScaler Patches After Two Zero-Days Exploited In Attacks

Citrix has released security updates for two critical NetScaler vulnerabilities exploited in attacks, following a weekend of warnings that prompted some organisations to take appliances offline.

The flaws, CVE-2026-88771 and CVE-2026-88772, affect NetScaler ADC and NetScaler Gateway. Both carry CVSS v4 severity scores of 9.5 and can enable remote code execution. Citrix’s security bulletin confirms observed exploitation and urges customers to install the relevant updates as soon as possible.

The disclosure changes the position facing administrators when the first warnings circulated: fixes are now available. However, organisations must also determine whether attackers gained access before those fixes were installed.