CVE intelligenceCISA KEV

CVE-2026-8452

Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability

Published Jun 30, 2026Sources checked Oct 28, 2026

9.8CRITICALCVSS out of 10

What this means

Actively exploited

CISA lists CVE-2026-8452 in its Known Exploited Vulnerabilities catalog, which means exploitation has been observed. The entry applies to Citrix NetScaler ADC and NetScaler Gateway.

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

What to do next

Remediation and response

Citrix Security Bulletins guidance

Vendor revision: Jul 20, 2026

Vendor remediation details

Cloud Software Group strongly urges affected customers of NetScaler ADC and NetScaler Gateway to install the relevant updated versions as soon as possible. NetScaler ADC and NetScaler Gateway 14.1-72.61 and later releases NetScaler ADC and NetScaler Gateway 13.1-63.18 and later releases of 13.1 NetScaler ADC 14.1-FIPS 14.1-72.61 FIPS and later releases of 14.1-FIPS NetScaler ADC 13.1-FIPS and 13.1-NDcPP 13.1.37.272 and later releases of 13.1-FIPS and 13.1-NDcPP CVE-2026-13474 Customers must upgrade to the above-mentioned NetScaler firmware versions that include the fix and update their configuration as described below. Configure the Http2SmallWndTimeout parameter, which controls the timeout (in seconds) for HTTP/2 small‑window stalled streams. For appliances using HTTP Strict Profiles, this parameter defaults to 30 seconds, and the fix is effective immediately after the upgrade. For appliances NOT using HTTP Strict Profiles, the default value is 0, and in that case, merely upgrading to the builds containing the fix WILL NOT address the vulnerability completely. In this case, customers must manually set Http2SmallWndTimeout to 30 seconds. Please note that Http2SmallWndTimeout is a new parameter and is only available in the firmware builds that contain the fix. Configuration command: set ns httpProfile -http2SmallWndTimeout

Vendor-listed releases

NetScaler ADC and NetScaler Gateway 14.1-72.61 and later releases
NetScaler ADC and NetScaler Gateway 13.1-63.18 and later releases of 13.1
NetScaler ADC 14.1-FIPS 14.1-72.61 FIPS and later releases of 14.1-FIPS
NetScaler ADC 13.1-FIPS and 13.1-NDcPP 13.1.37.272 and later releases of 13.1-FIPS and 13.1-NDcPP

CISA KEVListedObserved exploitation

EPSS1.0%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors1Source-linked actor relationships

Overview

What is CVE-2026-8452?

Memory overflow vulnerability NetScaler ADC and NetScaler Gateway leading to unpredictable or erroneous behavior and Denial of Service if the appliance is configured as a Gateway (SSL VPN, ICA Proxy, CVPN, RDP Proxy) or AAA virtual server

Source: NVD

CISA says:Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.CISA catalog due date Aug 29, 2026