New Citrix NetScaler zero-day exploited, US and Australia issue warnings

· Cybersecurity · United States

Citrix has released security updates for a high-severity memory overflow flaw in NetScaler ADC and NetScaler Gateway, tracked as CVE-2026-88779 with a CVSS score of 8.7, which has been exploited in targeted zero-day attacks capable of knocking SAML deployments offline. The company confirmed the new zero-day emerged just days after it patched two other exploited flaws. Citrix said it was "tracking a newly observed issue" affecting some customer-managed NetScaler deployments but claimed the problem was not connected to the earlier vulnerabilities. US and Australian authorities issued warnings about the latest vulnerability following Citrix's NetScaler advisory, as cybersecurity experts again raised alarm over the repeated targeting of the widely deployed appliances.

Why it matters：NetScaler appliances sit at the edge of countless enterprise and government networks, so a zero-day arriving days after patching two others signals attackers are deliberately racing defenders on a critical access gateway.

Key points

  • CVE-2026-88779 is a memory overflow flaw rated 8.7 on the CVSS scale.
  • Exploitation is linked to targeted attacks that can take SAML deployments offline.
  • The flaw surfaced days after Citrix patched two other actively exploited NetScaler issues.

Sources (original reporting)

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