Citrix NetScaler Vulnerability – Actively Abused Zero-Day

August 2025 Citrix confirmed several critical vulnerabilities (including CVE-2025-7775) in NetScaler ADC and Gateway. This is a zero-day that is already being actively abused by attackers. Tens of thousands of systems worldwide are vulnerable, including hundreds in the Netherlands. The severity is high: the National Cyber Security Center (NCSC) and CERT-EU warn that this vulnerability can cause direct remote code execution, resulting in attackers being able to gain complete control over corporate networks.

For Dutch organizations – from SMEs to government – this is not a far cry. These are systems that often perform critical functions, such as authentication (AAA), load balancing and remote access. Without a timely patch, companies risk data breaches, downtime and financial losses.

At ALTA-ICT, we help organizations with rapid patching, monitoring and compliance according to ISO27001, NEN7510 and BIO. In this blog you will read:

What CVE-2025-7775 is and why it is relevant to the Netherlands
How to effectively patch and mitigate the vulnerability
What challenges Dutch companies face
What the ROI is of good patch management and 24/7 monitoring
How the ALTA-ICT approach stands out

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What is CVE-2025-7775 and why relevant for Dutch companies?

Definition: buffer overflow in NetScaler ADC/Gateway, misuse leads to RCE/DoS
Context: 21,500 vulnerable systems worldwide >, of which 475 are in the Netherlands (source: Techzine)
Sector impact: healthcare (EHR access), financial (secure payments), government (DigiD integrations)
NCSC advisory: immediate patching, no mitigations available
Misconceptions: ‘Only large companies are targeted’ → SMEs also affected by automated scans

How do you patch CVE-2025-7775? Practical guide

Step 1 – Inventory

Determine which NetScaler version is running
Use Citrix/NetScaler tooling to detect vulnerability

Step 2 – Updating

Safe versions:
- 14.1-47.48+
- 13.1-59.22+
- 13.1-37.241 (FIPS/NDcPP)
- 12.1-55.330 (FIPS/NDcPP)
Cloud environments already patched, on-premise systems not

Step 3 – Configuration check

Gateway/AAA virtual servers
IPv6-bound LB servers
HDX-CR servers

Step 4 – Monitoring

Turn on IDS/IPS logging
Monitor 24/7 for abnormal behavior

Step 5 – Awareness

Train IT teams on incident response

Challenges for Dutch companies

Patch backlogs: limited capacity at SMEs
Compliance pressure: AVG/NEN7510 requires swift action
Shadow IT: unpatched test and dev environments
Downtime fear: patching without disruption

Solutions

Automated patch management
Redundancy plans for uptime (99.9% SLA)
Awareness training for employees

ROI of timely patch management

Cost of data breach NL average: €4.2 million (IBM 2025 report)
Average downtime without patch: 36 hours → revenue loss + reputational damage
With ALTA-ICT patching: 40% faster turnaround time
Compliance advantage: audit-ready within 72 hours

The ALTA-ICT approach

At ALTA-ICT, we offer:
✅ ISO27001/NEN7510 certified patch and security management
✅ 24/7 SOC monitoring from Dutch data centers
✅ AVG/BIO compliance for healthcare, government and financial
✅ Personalized approach for SMEs – cost-effective and without downtime

We combine tooling, human expertise and Dutch context.

FAQ

1. Has CVE-2025-7775 already been misused?
Yes, confirmed exploits in the wild.

2. Are there any workarounds available?
No, only patching works.

3. How do I know if my system is vulnerable?
Check your NetScaler version or use Citrix tooling.

4. Are cloud variants also vulnerable?
No, those are automatically patched.

5. Does ALTA-ICT provide assistance?
Yes, we do emergency scans and immediate patch management.

Conclusion

The NetScaler vulnerability CVE-2025-7775 shows once again how vulnerable Dutch companies are to zero-day attacks. With hundreds of unprotected systems in the Netherlands, immediate action is required. Only patching offers protection – and it must be done quickly.

At ALTA-ICT, we help companies not only with patching, but also with continuous monitoring, compliance and strategic IT security. In doing so, we reduce risks, minimize downtime and ensure a future-proof IT environment.

👉 S chedule a free consultation with our experts today.