Critical NetScaler ADC and Gateway Vulnerabilities

Overview

• Vendor: NetScaler (Citrix)

• Products: NetScaler ADC, NetScaler Gateway

• CVE(s): CVE-2026-3055, CVE-2026-4368

• Overall Severity: Critical (highest CVSS 9.3)

• Date: 24 March 2026

Summary

NetScaler has released a security advisory for a critical vulnerability in NetScaler ADC and NetScaler Gateway when configured as a SAML Identity Provider. The issue stems from insufficient input validation and may lead to memory overread. Organisations using SAML IDP configurations should prioritise remediation.

Affected Version

The following supported versions of NetScaler ADC and NetScaler Gateway are affected by the vulnerabilities: 

CVE-2026-3055:

• NetScaler ADC and NetScaler Gateway 14.1 BEFORE 14.1-66.59

• NetScaler ADC and NetScaler Gateway 13.1 BEFORE 13.1-62.23

• NetScaler ADC FIPS and NDcPP BEFORE 13.1-37.262

CVE-2026-4368:

• NetScaler ADC and NetScaler Gateway  14.1-66.54

Vulnerability Breakdown

CVE-2026-3055 - Memory Overread due to insufficient input validation

• Severity: Critical

• CVSS: 9.3

• Description: Insufficient input validation in NetScaler ADC and NetScaler Gateway when configured as a SAML Identity Provider (SAML IdP) can lead to a memory overread.

• Impact: Potential exposure of sensitive information from memory, which may support further compromise.

• Conditions: Appliance is configured as a SAML IdP.

• Notes: Prioritise internet-facing appliances and SSO-related deployments.

CVE-2026-4368 - Race condition leading to user session mix-up

• Severity: High

• CVSS: 7.7

• Description: A race condition in NetScaler ADC and NetScaler Gateway may lead to a user session mix-up.

• Impact: Possible session confusion or unintended access to another user session context.

• Conditions: See vendor bulletin for full exploitation prerequisites.

• Notes: Treat as urgent for environments providing remote access or authentication services.

Mitigation

• Apply the latest vendor updates for NetScaler ADC and NetScaler Gateway as a priority.

• If SAML IdP is enabled on NetScaler, prioritise patching those appliances first.

• Reduce exposure where possible:

  • Restrict management interfaces to trusted networks.

  • Limit external access to only required services.

• Validate authentication and access controls:

  • Enforce MFA for all administrative access.

  • Review privileged access and SSO configurations.

• Monitor for indicators of compromise and anomalous authentication behaviour.

Summary for IT Teams

• Products: NetScaler ADC, NetScaler Gateway

• Threat level: Critical (CVSS 9.3)

• Action required: Patch immediately, prioritising appliances configured as SAML IdP. Review admin access controls and monitor for unusual session or authentication activity.

Reference

• NetScaler ADC and NetScaler Gateway Security Bulletin

Need Help?

If your organisation needs assistance assessing exposure or deploying emergency updates for NetScaler ADC and NetScaler Gateway, contact Secure ISS on 1300 769 460.