External risk intelligence

NetScaler ADC and Gateway Memory Overflow Denial of Service Vulnerability

CVE advisoryKnown Exploit

CVE-2026-8452

The vulnerable products, NetScaler ADC and NetScaler Gateway, are designed to function as internet-facing edge gateways, SSL VPNs, and authentication portals. These appliances are inherently deployed at the network perimeter to manage and provide secure access to internal resources from the public internet.

Memory Corruption

Citrix Netscaler Application Delivery Controller

before 13.1-37.27213.1 to before 13.1-63.1814.1 to before 14.1-72.6114.1-66.68

Halo Surface Signal: 5 out of 5 — more likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A memory overflow vulnerability has been identified in NetScaler ADC and NetScaler Gateway, potentially causing unpredictable behavior or denial of service when configured as a gateway for services like SSL VPN or ICA proxy. The main concern is to confirm relevance and exposure within our environment.

Flaw in network gateway software can disrupt services.
Affects internet-facing access points for company resources.
Confirm if our gateway configurations are exposed.

Attack Path

How an attacker could exploit the issue

An attacker could reach this vulnerability by sending specially crafted network traffic to a NetScaler appliance that is configured to handle SSL VPN, ICA Proxy, CVPN, or RDP Proxy services. If the appliance is running a vulnerable version, this traffic could trigger a memory overflow, leading to unpredictable behavior or a denial-of-service condition.

Unauthenticated network access required.
Specially crafted network traffic triggers overflow.
Denial of service or erratic behavior.

Live Threat

Current exploitation, exposure, and threat context

When configured as a Gateway, NetScaler ADC and NetScaler Gateway could experience unpredictable behavior or denial of service due to a memory overflow.

Service availability could be affected.
Unpredictable or erroneous behavior may occur.
Denial of service can disrupt operations.

Operational Fix

Recommended remediation, mitigation, and detection steps

Application owners and infrastructure teams are likely responsible for managing NetScaler ADC and NetScaler Gateway appliances. The immediate priority is to identify all instances of the affected technology, determine their exposure and criticality, and assign an accountable owner for remediation planning.

Identify appliance deployment and exposure.
Verify business-criticality and owner.
Plan risk-based remediation.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is NetScaler ADC and NetScaler Gateway?

NetScaler ADC is an application delivery controller that optimizes and secures web traffic, while NetScaler Gateway provides secure remote access to internal resources. Organizations frequently deploy these products at the network perimeter to manage SSL VPN connections, application proxies, and authentication services for external users.

What does CWE-119 mean for CVE-2026-8452?

CWE-119 refers to improper restriction of operations within the bounds of a memory buffer. In the context of CVE-2026-8452, it means the software does not properly manage memory when processing network data, which can lead to a memory overflow. This overflow causes the appliance to crash or behave erratically, resulting in a denial-of-service condition.

How is this memory overflow triggered?

The flaw is triggered by sending specially crafted network traffic to an affected NetScaler appliance. The vulnerability specifically requires the device to be configured as a gateway, such as for SSL VPN, ICA Proxy, or RDP Proxy functions. Appliances not configured as a gateway or those running unaffected versions are not susceptible to this specific trigger path.

Do I need to worry about this vulnerability?

Yes, if you use these products as internet-facing gateways. Halo Surface Signal identifies these devices as high-priority because they are inherently designed to sit at the network edge to provide public-facing services. Since the vulnerability is remotely exploitable without authentication, any appliance reachable from the internet is a primary concern.

What should I do to respond to CVE-2026-8452?

First, identify all NetScaler ADC and Gateway instances in your environment and check their version and configuration. Confirm if they are acting as gateways, as these are the most critical. Coordinate with infrastructure teams to review official vendor documentation for the necessary updates or mitigation steps to resolve the memory overflow issue.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.