Research · Aug 19, 2026 · ZeroDay Catalog
Critical Authentication Bypass Vulnerability in Citrix NetScaler Products
A critical authentication bypass vulnerability has been identified in Citrix NetScaler ADC and Gateway, allowing remote exploitation by unauthenticated attackers.
What changed
On August 19, 2026, Citrix published a security advisory addressing CVE-2026-19490, a severe authentication bypass vulnerability in its NetScaler ADC and NetScaler Gateway products. This vulnerability has a CVSS v4.0 base score of 9.3, indicating its critical nature and potential impact.
- The vulnerability allows remote exploitation without user interaction.
- Unauthenticated attackers can bypass authentication mechanisms.
- The issue is particularly concerning due to the common deployment of these products at network perimeters.
Who is affected
Organizations utilizing Citrix NetScaler ADC and NetScaler Gateway are at risk due to this vulnerability. Given the widespread use of these products, the potential for exploitation is significant.
- Enterprises relying on Citrix NetScaler for application delivery and load balancing.
- Organizations with NetScaler Gateway for secure remote access.
- Any network infrastructure positioned near the perimeter using these products.
What to do
Immediate action is required to mitigate the risks associated with CVE-2026-19490. Administrators should prioritize patching affected systems and reviewing security configurations.
- Apply the latest security updates provided by Citrix as soon as possible.
- Review and enhance network perimeter security measures.
- Monitor for unusual activity that may indicate exploitation attempts.