NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2025-6543

NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2025-6543

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Article ID: CTX694788

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Updated On:

Description

NetScaler ADC and NetScaler Gateway contain the vulnerability mentioned below:

CVE-ID 

Description  Pre-conditions CWE CVSSv4

CVE-2025-6543

Memory overflow vulnerability leading to unintended control flow and Denial of Service

NetScaler must be configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer

CVSS v4.0 Base Score: 9.2

(CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L)

What Customers Should Do

Exploits of CVE-2025-6543 on unmitigated appliances have been observed.

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 14.1-47.46 and later releases
  • NetScaler ADC and NetScaler Gateway 13.1-59.19 and later releases of 13.1
  • NetScaler ADC 13.1-FIPS and 13.1-NDcPP 13.1-37.236 and later releases of 13.1-FIPS and 13.1-NDcPP. Customers should contact support - https://support.citrix.com/support-home/home to obtain the 13.1-FIPS and 13.1-NDcPP builds that address this issue.


Note: NetScaler ADC and NetScaler Gateway versions 12.1 and 13.0 are now End Of Life (EOL) and no longer supported. Customers are recommended to upgrade their appliances to one of the supported versions that address the vulnerabilities. 

Cloud Software Group has published a related blog at https://www.netscaler.com/blog/news/netscaler-critical-security-updates-for-cve-2025-6543-and-cve-2025-5777/ which contains further context.

Environment

The information on this page is being provided to you on an "AS IS" and "AS-AVAILABLE" basis. The issues described on this page may or may not impact your system(s). Cloud Software Group, Inc. and its subsidiaries (collectively, "Cloud SG") make no representations, warranties, or guarantees as to the information contained herein. ANY AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY, NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. BY ACCESSING THIS PAGE, YOU ACKNOWLEDGE THAT CLOUD SG SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN. Cloud SG reserves the right to change or update the information on this page at any time. We accordingly recommend that you always view the latest version of this page. The information contained herein is being provided to you under the terms of your applicable customer agreement with Cloud SG, and may be used only for the purposes contemplated by such agreement. If you do not have such an agreement with Cloud SG, this information is provided under the cloud.com Terms of Use, and may be used only for the purposes contemplated by such Terms of Use.

Issue/Introduction

Severity - Critical

Description of Problem

A vulnerability has been discovered in NetScaler ADC (formerly Citrix ADC) and NetScaler Gateway (formerly Citrix Gateway). Refer below for further details.

Affected Versions

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

  • NetScaler ADC and NetScaler Gateway 14.1 BEFORE 14.1-47.46
  • NetScaler ADC and NetScaler Gateway 13.1 BEFORE 13.1-59.19
  • NetScaler ADC 13.1-FIPS and NDcPP  BEFORE 13.1-37.236-FIPS and NDcPP


NetScaler ADC 12.1-FIPS is not affected by this vulnerability.


Note: NetScaler ADC and NetScaler Gateway versions 12.1 and 13.0 are now End Of Life (EOL) and are vulnerable. Customers are recommended to upgrade their appliances to one of the supported versions that address the vulnerabilities. 


Additional Note: Secure Private Access on-prem or Secure Private Access Hybrid deployments using NetScaler instances are also affected by the vulnerabilities. Customers need to upgrade these NetScaler instances to the recommended NetScaler builds to address the vulnerabilities. 

This bulletin only applies to customer-managed NetScaler ADC and NetScaler Gateway. Cloud Software Group upgrades the Citrix-managed cloud services and Citrix-managed Adaptive Authentication with the necessary software updates.

Additional Information

Changelog

2025-06-25 Initial Publication
2025-06-27 Inclusion of a link to an additional Cloud Software Group blog post for CVE-2025-6543