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Critical Citrix NetScaler Vulnerability Actively Exploited – Immediate Action Needed

A serious security flaw in Citrix NetScaler products has been found and is already being exploited by attackers. This flaw allows unauthorised users to run harmful commands on affected systems, potentially leading to data breaches or service disruptions. Small organisations using these products should act quickly to reduce risk.

28 September 2026

Reference: CVE-2026-88771

1. What is being reported?

There is a critical vulnerability in Citrix NetScaler ADC and Gateway devices caused by improper input validation. This means attackers can send specially crafted requests to these devices and execute commands without needing to log in. The issue affects certain versions before specific updates were released.

2. What this means in plain English

If your organisation uses Citrix NetScaler devices to manage internet traffic or remote access, attackers could take control of these devices remotely. This can lead to theft of sensitive information, interruption of services, or further attacks inside your network. The risk is high because the vulnerability is actively being exploited.

3. Could this affect a small business?

Small businesses or charities using Citrix NetScaler ADC or Gateway products in the affected versions could be at risk, especially if these devices are accessible from the internet. Organisations not using these products or using updated versions are unlikely to be affected.

4. What to do now

  • Check if your organisation uses Citrix NetScaler ADC or Gateway devices and identify their software versions.
  • Contact your IT provider or software supplier immediately to confirm if your devices are affected and to arrange for urgent updates or mitigations.
  • If updates are not yet available, follow vendor instructions for temporary mitigations or consider disconnecting the devices from the internet until fixed.
  • Review your network exposure to ensure these devices are not unnecessarily accessible from outside your organisation.

5. Ask your IT provider

Can you confirm whether our Citrix NetScaler devices are affected by CVE-2026-88771, and what steps are being taken to apply the necessary security updates or mitigations?

6. Bottom line

If you use Citrix NetScaler devices, act now to update or protect them against a critical vulnerability that attackers are already exploiting.

Information based on CISA KEV, NVD, and multiple reputable cybersecurity news reports.

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