30 September 2026
Reference: CVE-2026-88777
1. What is being reported?
There is a memory overflow vulnerability in certain versions of Citrix NetScaler ADC and Gateway. This means that attackers could cause the system to malfunction or stop working by sending specially crafted data. The problem affects specific versions released before certain updates.
2. What this means in plain English
If your organisation uses Citrix NetScaler ADC or Gateway and has not updated to the latest versions, attackers could disrupt your network services or cause outages. This could impact your ability to access important systems or online services, potentially leading to downtime or loss of productivity.
3. Could this affect a small business?
Small businesses or charities that use Citrix NetScaler ADC or Gateway devices, especially older versions, could be affected. If you do not use these Citrix products, this vulnerability does not apply to you.
4. What to do now
- Check if your organisation uses Citrix NetScaler ADC or Gateway products.
- Ask your IT provider whether your Citrix devices are running affected versions.
- Apply the latest Citrix updates or patches as soon as possible to fix the vulnerability.
- Monitor your systems for unusual behaviour and report any issues to your IT support.
5. Ask your IT provider
Can you confirm if our Citrix NetScaler ADC or Gateway devices are affected by CVE-2026-88777, and have the necessary security updates been applied?
6. Bottom line
If you use Citrix NetScaler ADC or Gateway, update it now to avoid service disruptions caused by this actively exploited vulnerability.
Information based on CISA KEV, NVD, and reputable security reporting.