Actively exploited in the wild
Citrix NetScaler ADC and Gateway Buffer Overflow Vulnerability
Citrix - NetScaler ADC and Gateway · Listed in the CISA KEV since 2025-06-30. This indicates confirmed attacks in production environments.
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CVE-2025-6543
CriticalCVSS 9.8KEVSummary
Memory overflow vulnerability leading to unintended control flow and Denial of Service in NetScaler ADC and NetScaler Gateway when configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server.
Risk Assessment
An attacker can cause service disruption or take control of the device, potentially leading to network downtime and security breaches.
Recommendation
Apply the patches provided by the vendor and monitor systems for unusual activity.
Other vulnerabilities in NetScaler ADC
See all- CVE-2026-8655Critical
Multiple memory overflow vulnerabilities in NetScaler ADC and NetScaler Gateway can lead to unpredictable or erroneous behavior and Denial of Service (DoS). The vulnerability occurs when NetScaler ADC is configured as an Oracle load balancer, DNS proxy, or DNS recursive resolver.
- CVE-2025-7775CriticalActively exploited
Memory overflow vulnerability leading to Remote Code Execution and/or Denial of Service in NetScaler ADC and NetScaler Gateway when NetScaler is configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server, or in specific LB and CR virtual server configurations with IPv6 services.
- CVE-2026-8451High
Insufficient input validation in NetScaler ADC and NetScaler Gateway leads to memory overread when the device is configured as a SAML IDP.
- CVE-2026-13474High
The vulnerability allows a DoS attack via malformed HTTP/2 requests to NetScaler ADC and NetScaler Gateway. It occurs when HTTP/2 is enabled in the HTTP profile and associated with a virtual server (LB, CS, VPN) or a service configured on the device.
Original NVD description (English source)
Memory overflow vulnerability leading to unintended control flow and Denial of Service in NetScaler ADC and NetScaler Gateway when configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server