Summary Points
- A critical memory overflow vulnerability (CVE-2026-107406) in Citrix NetScaler ADC and Gateway can enable remote code execution or DoS attacks, especially on configurations as SAML IdP or SP.
- Exploitation of this flaw has not been observed in the wild, but it affects several versions prior to updates, risking unauthorized access and system disruption.
- Organizations using vulnerable versions must upgrade to patched releases (14.1-73.46, 13.1-64.29, and FIPS variants) to mitigate the high CVSS score (9.5) threat.
The Threat, Attack Techniques, and Targets
Citrix has released patches for a serious security flaw called CVE-2026-107406. This flaw is a memory overflow vulnerability. It can allow hackers to run malicious code or cause a shutdown of the system, known as a denial-of-service (DoS). The vulnerability has a high severity score of 9.5 out of 10. There is no evidence that hackers are actively exploiting it yet.
The attack depends on how NetScaler is set up. Cybercriminals need the system to be configured as a SAML identity provider (IdP) or service provider (SP). They can tell if the system is vulnerable by checking for specific entries in the configuration, such as “authentication samlAction” or “authentication samlIdPProfile.”
The flaw impacts various versions of NetScaler ADC and Gateway. These include versions set as SAML IdP or SP, or other earlier versions before certain updates. This affects many customer setups, especially those with secure private access hybrid systems.
Impact, Security Implications, and Remediation Guidance
If exploited, the flaw could let attackers run harmful code remotely or make systems unavailable. This threatens network security and could lead to data breaches or system outages. Because the flaw affects widely used configurations, it poses a significant risk to affected organizations.
Citrix recommends updating to newer versions to fix this issue. The patches are available in Citrix NetScaler ADC and Gateway versions 14.1-73.46 and later, as well as other recommended releases. Customers should check their current setup and upgrade accordingly.
If you want detailed steps for fixing this problem, you should obtain remediation guidance directly from Citrix or the relevant security authority.
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